Friday, 12 December 2025

How Often Does a Falling Rupee Drag the Sensex Down? The Surprising Patterns

How Often Does a Falling Rupee Drag the Sensex Down? The Surprising Patterns 12Dec2025



 
 

(The views expressed here are for information purposes only and should not be construed as a recommendation or investment advice. While the author is a CFA Charterholder with nearly 25 years of experience in financial markets, this content is intended to share general insights and does not constitute financial guidance. Please consult your financial adviser before taking any investment decision. Safe to assume the author has a vested interest in stocks / investments discussed if any.)

 

(Don't miss Timeline of Events and FRED Charts at the end of the blog)

 


 

Graph showing Dollar Rupee Exchange Rate 1973 to 2025 (St Louis Fed)

 

 

If you’ve followed financial news for any length of time, you’ve seen this movie before:

“Rupee crashes to a new low!”

"Rupee, Asia's worst currency!"

“Currency weakness threatens markets!”


Every now and then, headlines like these flash across screens and social media, instantly sparking anxiety among investors. And it’s understandable — a falling rupee feels like a sign that something big (and bad) is happening.

As someone who has followed the Indian economy and financial markets for over four decades, I’ve lived through some of the most dramatic currency moments in our history. 

I still remember the shock of the 1991 devaluation, the introduction of Liberalised Exchange Rate Management system (LERMS) soon after, the excitement and uncertainty around the unified (market determined) exchange rate in 1993, the sharp rupee wobble during the Asian Financial Crisis of 1997/1998 and of course, the global tremors of the 2013 taper tantrum.

Each of these moments came with loud headlines, anxious commentary and plenty of predictions about how a falling rupee would drag the stock market into chaos.

To give a better perspective, take a look at the chart above -- a long-term US dollar-Indian rupee exchange rate (USD INR) inverse graph stretching all the way back to 1973. It climbs steadily upward for five decades. At first glance, it looks like one long story of the rupee “falling.”

And yet…

During these same decades, the Sensex has grown since the early 1980s to over 85,000 today.

Put simply, the steady and largely natural depreciation of the rupee against the dollar has not stopped Indian equities from compounding wealth over time. A big part of this long-term rupee depreciation reflects higher cumulative inflation in India compared to the US over decades, rather than something fundamentally broken in the Indian economy.  

The resulting erosion of the rupee’s purchasing power (currency debasement) — an important topic in its own right — is best examined separately from the behaviour of Indian equities. 

When someone says a weak rupee leads to falling markets, it sounds believable. But actually, what does the data say?

This data-driven blog post, using episodes of rupee fall in the past 35 years, is an attempt to find out answers. Let's delve deep. 

 

What the above long-term FRED chart shows:

1973 to 1990  Rupee was not market determined (rupee weakned gradually)

1991 to 1998 Sharp rupee devaluation in 1991 and depreciation after LERMS in 1992 and unified (market determined) exchange rate in 1993

1999 to 2007 Somewhat stable rupee with episodes of rupee appreciation

2008 to 2025 Gradual rupee depreciation, Lehman Bros collapse, Taper Tantrum and COVID-19 

 

(article continues below)

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Related articles:

Does a Falling Rupee Hurt Indian Stocks? The Data Say "Not Really" 02Dec2025

Brief History of India's 1991 Forex Crisis and Gold Pledge 17Jun2024 

Why RBI Won't Favour a Strong Rupee? 03Jun2024

RBI Record Surplus Transfer to Government of India 23May2024

Understanding Real Sensex and Currency Debasement 14Mar2024 

Limited Direct RBI Forex Intervention to Stem Rupee Fall 13Jan2012 

 

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2 Follow-up Article

Last week, I explored this very 'rupee-fall-leads-to-market-fall' anxiety in a blog "Does a Falling Rupee Hurt Indian Stocks?" where I looked at 15 years of calendar-year data to understand whether a falling rupee generally drags Indian stocks down. The results showed no particular pattern in establishing a correlation betwen rupee weakness and Sensex movement.

But that analysis had one limitation: it used calendar-year movements, which often hide the real “shock periods” inside the year.

That’s what led to today’s follow-up. Instead of asking “How did the rupee and Indian stock market move over a whole year?”, this blog asks a sharper, more realistic question:

What actually happens when the rupee starts falling — right from the month the slide begins, until the point it peaks — and the rupee depreciation crosses 8 per cent?

In other words, this time I’m looking at actual episodes of sharp rupee weakness, not arbitrary year-end snapshots. The period may be short (one month), moderate (six months), or nearly a year — the common factor is a meaningful 8%+ rupee decline.

 

3 Historical Rupee Depreciation Episodes

India experienced 15 major rupee depreciation episodes between 1990 and 2022. These were driven by geopolitical shocks (like the 1990 Gulf War and 2008 Lehman Brothers collapse), domestic policy challenges (1991 Forex crisis, 2011 policy paralysis), global financial tightening (2013 taper tantrum), high current account deficit and COVID-19 pandemic-related pressures. 

Depreciation typically ranged from 6 per cent to 20 per cent. The largest drops occurred during the taper tantrum of 2013, the 1991 rupee devaluation, the 2008 global financial crisis (GFC) and the 2011 slowdown. Sensex performance during these periods varied widely: deep crashes in some episodes, strong rallies in others and mild moves in many cases.

 

What happened between 2022 and now? 

By the way, I also looked at the most recent phase — from 2022 to Dec2025: 

Between Oct2022 and Mar2024 (about 18 months), the rupee was surprisingly stable, trading in a fairly tight range of 81 and 83.5 against the dollar. 

From March 2024 to now (around 21 months), the rupee has gradually weakened from 83.5 to about 90.5, punctuated by one bout of volatility during the Dec2024–May2025 period rather than a sudden, disorderly slide.

A bit of context helps here. During the relatively calm phase between Oct2022 and Mar2024, the RBI was an active player in the forex market, net buying nearly USD 50 billion during 18-month period (for data, check Forex Data Bank - Update 26Nov2025 with charts 144 and 145). 

These purchases helped absorb inflows and kept the rupee trading in a narrow range, even as global conditions remained volatile. In other words, the rupee’s stability during this period wasn’t accidental — it was, at least in part, policy-managed rather than purely market-driven.

Ideally, a deeper analysis would also map each episode of rupee weakness to RBI’s forex intervention strategy during that exact period — whether the central bank was intervening heavily or largely staying on the sidelines. 

That, however, is a substantial exercise in itself, requiring careful compilation of intervention and balance-of-payments data across multiple episodes. To keep this post focused and readable, I’ve stayed away from that exercise for now. It’s a natural extension of this work — and something worth exploring separately another time. 

 

Here are the charts > 

1) Chart Showing Historical Episodes of Large Rupee Depreciation Versus Dollar - From 1990 To 2000:

2) Chart Showing Historical Episodes of Large Rupee Depreciation Versus Dollar - From 2008 To 2022: 

Please click on the charts to view better >

 


 

What the above two charts reveal?

Pattern Analysis: Rupee and Sensex Relationship

Rupee depreciation does not consistently lead to stock market crashes. Several periods show the rupee weakening while the Sensex actually gained, such as in 1991, 1992, 2018 and 2022. These cases often involved strong domestic economic cycles or supportive global liquidity. 

Market expectations also matter: if depreciation is anticipated, equity markets may remain stable or even rise (as mentioned in Section 5 below, beware of caveats, like, regime changes in exchange rate system and investment flows).

However, when depreciation coincides with a global “risk-off” crisis, the Sensex tends to fall sharply. Examples include the 2008 global financial crisis (GFC), the 2020 COVID-19 shock and the 1998 Asian financial contagion. These were broad global meltdowns where emerging markets saw heavy outflows.

The duration of the depreciation varies, from less than a week (1991 staged devaluation and 1993 volatility) to several months (1990 Gulf War, 2008 crisis, 2011 slowdown, 2018 tightening, 2022 Fed interest rate increase cycle (see Update 02Nov2025 with charts 141 to 143). 

The rupee decline in 2022 also coincided with the invasion of Ukraine by Russia. Longer episodes usually reflect broader macro cycles rather than sudden shocks.

Another interesting pattern is that there were not many episodes of high rupee decline in the period between 1999 and 2007 -- indicating a somewhat stable rupee during the period. After 2013, India attempted to build its foreigh exchange reserves more strongly. 

With high forex reserves, RBI's tactics to defend the rupee against any excess volatility may have sharpened post 2013.

 

Comparisons Across Episodes

The biggest rupee drops occurred during: 

the 2013 taper tantrum (-20.4%), 
the 1991 devaluation (-19.6%), 
the 2008 GFC crisis (-19.0%), 
the 2011  (-18%), and 
the 1990 Gulf War (-18.1%).

The worst Sensex declines were during:

the 2008 Lehman collapse (-50.3%), 
the 2020 COVID shock (-33.1%), 
the 1998 Asian Contagion (-23.7%),
the 2000 Dotcom Bubble Burst (-18.9%), and 
the 2011 Policy "paralysis" (-13.4%).

A key observation is that these two sets do not perfectly align. Large rupee depreciation does not necessarily produce an equity market crash; only when a global systemic crisis is involved do both fall sharply.  

Rupee weakness raises import costs and inflation risk, which can pressure markets. It also creates FPI flows uncertainty, though exporters may benefit, making the overall impact mixed. So, the narrative resonates strongly with several investors -- creating noise around "historically low rupee."

However, a sudden rupee fall could hurt the real economy in different ways, even if the Sensex doesn’t always react sharply:

A sharp rupee fall makes imports—especially crude oil, gas and fertilisers more expensive, pushing up inflation and pressuring household budgets.

Companies with unhedged foreign-currency borrowings may be negatively impacted.

Higher import bills widen the current account deficit (CAD), while fuel and fertiliser subsidies can increase the fiscal burden on the government.

Sudden currency instability raises uncertainty, prompting firms to delay capex decisions and making foreign investors more cautious about long-term commitments.

A sharp rupee fall can force the RBI to choose between supporting growth and controlling inflation—sometimes tightening liquidity or rates to steady the economic ship.  

 

Rupee Falls Sharply but Sensex Rises! 

There are a few instances when Sensex rose dramatically, despite sharp fall in rupee. The instances are:

Gulf War aftermath: Aug1990-Jun1991: Rupee depreciated by 18.1 per cent, but Sensex gained 10.3 per cent. 

During Aug 1990–Jun 1991, the rupee fell sharply because of the Gulf War and the balance-of-payments (BoP) crisis, yet the Sensex still rose. A key reason was the political transition in 1991, when a new government under PV Narasimha Rao took office with Manmohan Singh as finance minister. 

Markets expected major reforms, stabilisation and opening up of the economy.

So even though the currency was under pressure, the Sensex gained because investors were looking past the crisis and pricing in policy changes, reform momentum and long-term growth prospects triggered by the 1991 government shift and its push for radical economic reforms.


Feb1992-Mar1992: Harsha Mehta Boom: Sensex roared 52.7 per cent, even as rupee fell by 11.4 per cent. 

The Sensex rallied strongly because a massive liquidity-driven stock market boom was underway, fuelled by the Harshad Mehta Securities Scam. This bull run was so powerful that it overpowered any negative sentiment from the rupee fall.

Markets were rising on speculation, leverage and unusually high risk appetite—so the currency move didn’t matter. 

Lost decade: Interestingly, after the Harshad Mehta speculative boom inevitably collapsed, the Sensex remained stagnant for nearly a decade until 2003, a period often dubbed the "Lost Decade" for Indian equities.

 

As shown above, when rupee falls sharply:

Sometimes Sensex drops.
Sometimes Sensex rises.
Sometimes it barely reacts. 

So, when some expert tells you rupee depreciation is a harbinger of Indian stock market rout, don't believe them without checking the hard data. 😁 

 

4 Fred Charts 

Charts are often more intuitive for many investors, so the following visuals are included to show the extent of rupee depreciation using an inverse USD-INR graph. These charts are from St Louis Fed.

A. May2013 to Aug2013 Taper Tantrum: Rupee falls 20.4% (Sensex loses 11%) >

Between May2013 and Aug2013, the US Fed's taper tantrum triggered a sudden reversal of global liquidity as the Fed signalled an end to quantitative easing (QE). This led to sharp FPI outflows from India and other emerging markets

The resulting dollar shortage, wide current account deficit and loss of investor confidence combined to push the rupee down sharply. 

That the Fed later slowed down and clarified the tapering plan (calming the markets and stabilising the currencies) is a different matter.  


 

B. Jul1991 Rupee Devaluation in two stages: Rupee falls 19.6% (but Sensex gains 3.4%) >

On 01Jul1991 and 03Jul1991, Govt of India / RBI devalued the rupee versus the dollar, by 9 per cent and 11 per cent respectively. 

The Jul1991 rupee devaluation was forced by a severe balance-of-payments (BoP) crisis, with forex reserves down to just a few weeks of import cover. The Gulf War shock, rising oil prices and a collapse in external financing sharply reduced dollar inflows and investor confidence. 

An overvalued, administratively managed rupee had also hurt exports, making a two-stage devaluation unavoidable to restore competitiveness. 

 

C. May2008-Aug2008 Lehman Bros Collapse: Rupee Falls 19% (Sensex plummets 50.3%) >

The 2008 rupee collapse was triggered by the global financial crisis (GFC) and Lehman Brothers Collapse, which sparked massive risk-off sentiment and capital flight from emerging markets to the US. Foreign portfolio investors pulled out funds from Indian equities and debt, creating a sudden shortage of dollars. 

At the same time, rising oil and commodity prices widened the current account deficit, intensifying pressure on the currency.


(Note: in case you want to see more Fred charts, see the end of the article)

 

Caveats, Shortcomings and Additional Nuances

Even though the episode-based, data-driven approach offers a much sharper picture than simple calendar-year averages, it still comes with some limitations that readers should keep in mind:


a. The Sensex reflects only 30 stocks

While the Sensex often captures the direction of the market, its reaction to currency swings may differ from the broader indices, mid-caps or small-caps. Sectors heavily exposed to imports or exports may react far more strongly than the headline index. 

Analysis of sectoral indices is outside the scope of this informal and educative piece. IT Services, export-oriented automakers and pharma usually benefit from INR fall, but import-heavy sectors, like, airlines, oil market companies (OMCs) and electronics firms may react negatively to rupee depreciation.  

b. Currency movements reflect many forces, not just domestic factors

A sharp fall in the rupee may be due to global dollar strength, US monetary policy changes, geopolitical risk or weak capital flows — not necessarily India-specific stress. So the “INR fall leads to Indian stocks fall” logic doesn’t always hold.

c. Stocks and the rupee don’t always move at the same time

Currency markets and equity markets have different participants and different drivers. In several episodes, stocks may have fallen before the rupee weakened (anticipating risk), recovered while the rupee was still falling, or moved independently due to domestic policy reforms, earnings cycles or global liquidity. This time mismatch is an unavoidable challenge when defining “episodes.”

d. Results depend on the chosen time window


By design, the analysis identifies sharp falls of 8%+ over one to twelve months. But had we chosen 6 per cent, or 12 per cent, or used 2–18 month windows, the list of episodes — and some of the conclusions — might differ. 

e. Sensex returns can look very different depending on the measurement point

Even within the same episode, the Sensex may have dipped sharply mid-way, recovered before the rupee stabilised, or rallied despite currency volatility. Charts often smooth out this noise, so the lived experience may feel more volatile. 

f. Correlation does not imply causation

Even if the Sensex falls during an episode of rupee depreciation, that doesn’t prove the rupee fall caused the market decline. Many a time both are responding to the same macro stress — global risk-off, Fed tightening, crude oil price spikes and others. 

g. Recovery periods vary widely

Different INR-fall episodes have different recovery durations. A 10-per-cent depreciating spell may reverse in a few weeks in one era, and take a year in another — making comparisons tricky.

h. Regime change in exchange rate system

Another important limitation is that the exchange-rate regime itself has changed over time. Before 1993, the rupee was not market-determined — it moved under administrative controls, dual rates (LERMS) and one-off devaluations, making pre-1993 movements fundamentally different from today’s market-driven currency behaviour. 

After the 1993 unified exchange rate, the INR began responding much more to global flows, sentiment and domestic fundamentals, which means older episodes are not strictly comparable with post-1993 data. 

Curiously, the International Monetary Fund (IMF) recently dubbed India's exchange rate arrangement as "crawl-like."

i. Regime change in investment flows

Post-2016, the Sensex has become more responsive to domestic institutional investor (DII) flows (buttressed by EPFO Investments) than to foreign portfolio investor (FPI) flows. 

This means that even during periods of sharp INR depreciation driven by FPI outflows, strong DII buying has often cushioned the market, weakening the traditional link between rupee weakness and Sensex declines.


j. RBI forex intervention

A further complication is Reserve Bank of India's (RBI) intervention policy: sometimes the central bank intervenes heavily in the forex market and sometimes it allows the rupee to adjust freely, making it difficult to interpret how “natural” or policy-altered each rupee fall truly was.

 

6 Overall Insights and Takeaways

Rupee depreciation alone is a poor predictor of Indian equity market performance. Markets react negatively only when depreciation signals broader global distress and geopolitical risks. In many episodes, equities have stayed strong despite currency weakness. 

Export-oriented sectors usually benefit from a weaker rupee, while import-heavy sectors suffer.

India has survived several depreciation cycles and has strengthened structurally over time thanks to higher (somewhat excess) forex reserves, manageable external debt metrics and a stronger banking system. This implies future depreciation episodes are more likely to be gradual than sudden.

However, a few weak points from investment flows perspective is the continuous FPI selling of Indian equities in recent years (though they are buyers in debt segment) and the tumbling foreign direct investment (FDI) flows into India.  

 

7 Investment Implications? 

A key takeaway for Indian investors is that a falling rupee does not automatically signal trouble for the entire stock market. Instead of reacting to currency headlines, investors should focus on portfolio diversification and sector / market capitalisation exposure, because exporters may gain while import-heavy sectors may temporarily struggle. 

Exchange rate volatility also reinforces the importance of asset diversification—across equities, debt, gold and even global assets where appropriate. Since the Sensex often responds more to fundamentals / earnings, liquidity and sentiment than to currency moves alone, long-term investors are usually better off staying disciplined rather than making knee-jerk exits. 

Most importantly, understanding the historical patterns of INR-fall episodes can help investors avoid panic, stay patient and position portfolios more thoughtfully during periods of currency stress. Finally, monitoring global cues, such as US Federal Reserve actions, geopolitical risks or crude oil prices, is crucial for making informed investment decisions. 

Indian investors are anxiously waiting for India to clinch a win-win trade deal with the US.  

 

- - - 

 

 

 

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Additional Fred Charts:

FRED Charts (from St Louis Fed) showing various episodes, between 1990 and 2022, of Sharp Rupee Fall >






 




 

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Timeline of Events: 1949 to 2022:

19Sep1949: Rupee devaluation  by 30.5% as a defensive measure consequent to the devaluation by other 'sterling area' countries (in those days, Rupee was pegged to British Pound Sterling) -- India' PM was Jawaharlal Nehru and RBI governor was Benegal Rama Rau

 

24Jan1966: Indira Gandhi, for the first time, became India's prime minister

06Jun1966: Rupee devaluation from 4.76 to 7.50 to the dollar, means rupee devalued by 36.5% vs dollar --  Indira Gandhi was India's PM and PC Bhattacharya was RBI governor

 

1989 to 1991: India had seen four prime ministers 

1990 to 1991: India's Forex Crisis / Balance of Payments Crisis

Aug1990: Gulf War broke out with Saddam Hussein’s Iraq invading Kuwait

Nov1990: Chandra Shekhar formed the Central government with Congress (I) party’s outside support

Mar1991: Chandra Shekhar resigned as prime minister and his government became a caretaker government (after Rajiv Gandhi's Congress (I) govt withdrew support)

21Jun1991: PV Narasimha Rao of Congress (I) took over as India’s prime minister  

01Jul1991: Rupee devaluation by 9% -- India government headed by PM Narashimha Rao and FM Manmohan Singh) and RBI Governor S Venkitaramanan)

03Jul1991: Rupee devaluation again, this time by 11% (the total two-stage devaluation amounted to 19%)-- India government (PM Narashimha Rao and FM Manmohan Singh) and RBI (Governor S Venkitaramanan)

 

01Mar1992: LERMS (Liberalised Exchange Rate Management System) - a dual exchange rate system for dollar-rupee - was introduced by RBI

1992: India's Forex crisis blows over 

27Feb1993: Unified exchange rate system (a market-determined dollar-rupee exchange rate system), replacing LERMS, was introduced by RBI  


Jul1997: Thailand floats the Thai Baht after months of speculative attacks and depleting forex reserves (start of 1997/1998 
Asian Financial Contagion)

Aug1997: Indonesia floats the Rupiah, allowing Rupiah's free fall (financial panic in Asia) 
(spread of 1997/1998 Asian Financial Contagion)

23Oct1997: Hong Kong stocks plummet by 10% after HK raises interest rates sharply to defend HK dollar's peg against the dollar (this triggered a global financial shock) (
Asian Financial Contagion)

Nov1997: South Korea requests IMF aid (IMF later grants USD 57 billion) 
Asian Financial Contagion)

Nov1997 and Dec1997: Asian Financial Contagion negatively impacted India; with INR losing 7.7% vs USD 

May1998: Indonesia president Suharto resigns after mass protests (following currency collapse, supply chain disruption and price rises), elite defection and loss of military support 
(peak of Asian Financial Contagion)

 

11May1998: India conducts three nuclear tests

13May1998: India conducts two additional nuclear tests

May-Aug1998: INR depreciated by 8.6% during the period; after India conducted five nuclear tests in May1998 triggering Western sanctions on India 

 

Mar2000: start of Dotcom bubble burst; tech stocks on Nasdaq crash

Mar2000: the tech market crash triggers capital outflows from emerging markets

May2000: FPI equity selling leads to INR weakness and higher oil import bill and Sensex fall  

Jul2000: INR weakness, Sensex fall and FPI outflows continue  

May-Oct2000: gradual rupee depreciation of 6.8%

 

Jan–Mar2008: Global financial markets show stress after US subprime crisis intensifies in 2007

16Mar2008: Bear Stearns was “saved” through a government-brokered acquisition; JP Morgan Chase acquires Bear Stearns in a bailout

Mar2008: The US government, led by president George Bush Jr, created a moral hazard by bailing out Bear Stearns -- financial markets assumed the US government would step in to stem any financial crisis or bank collapse in the future. [The assumption allowed the financial markets to remain complacent about subprime crisis, mortgage crisis (relating or mortgage-backed securities or MBS, Collateralised Debt Obligations or CDOs and Credit Default Swap or CDS) and other financial vulnerabilities. The markets were utterly shocked when the US gov't decided not to intervene when Lehman Borthers collapsed in Sep2008].

May2008: Crude oil prices peak (USD 140/barrel) leading to increases in India’s import bill, widening Trade deficit and weaker rupee

Aug2008: US mortgage crisis spreads to banks globally, bearish sentiment worldwide

Sep2008: flight to safety (dollar demand), with money moving to the US

15Sep2008: Lehman Brothers in the US declares bankruptcy, sending shock waves across the world and ultimately leading to Global Financial Crisis (GFC)

Sep-Oct2008: massive FPI outflows from India; heavy Sensex crash; INR fall

May-Oct2008: rupee depreciates by 19% (due to events described above) 

 

Aud-Sep2011: Indian rupee falls pressured by Eurozone Sovereign Debt Crisis, shortage of dollars globally (safe have demand for dollar) despite S&P debt downgrade of the US; FPI outflows from India; Sensex falls; growing current account deficit in India; 

Oct2011: Strong Dollar gain pressures rupee and other emerging markets currencies

Jul-Nov2011: US dollar gains by 10% (US dollar index) putting pressure in rupee

Apr-Aug2011: There was absolutely no RBI Forex intervention  

Sep-Nov2011: RBI Forex Intervention: RBI intervenes heavily in Forex market to defend rupee by selling US dollars worth USD 4.7 billion during Sep-Nov2011

 

Feb-Jun2012: INR falls by 14.2%; due to concerns over weak global growth, US / Eurozone stagnation, India's widening current account deficit, FPI outflows from India, India's rising inflation and policy uncertainty from UPA gov't 

 

22May2013: Fed chair Ben Bernanke avers that the Fed is prepared to reduce its purchase of mortgage securities gradually (markets dub this as 'Taper Tantrum') 

Jun2013: FPI outflows from India; INR weakens and rising current account deficit concerns

Jul2013: Inflationary pressures in India exacerbated by INR fall; and global risk aversion

May-Aug2013: INR plummets by 20.4% (events described above)

 

Apr-Oct2018: Rupee depreciates by 12.6% due to US dollar index surging; US interest rate hikes, rising crude oil prices; FPI outflows from India; and widening India's current account deficit 

 

24Feb2022: Russia invades Ukraine triggering massive rise in commodity prices, including, crude oil and agri commodities stoking inflationary pressures globally 

Jan-Jun2022: Aggressive selling of Indian stocks by FPIs amounting to Rs 2.17 lakh crore 

Jan-Jun2022: Steep rise in US 10 year bond yield by almost 200 basis points 

Feb-Oct2022: aggressive Fed funds rate hikes (rate hikes continued till Aug2023) following surging US CPI inflation between Feb2021 and Jun2022) 

Feb-Oct2022: RBI Forex intervention in the 9-month period amounted to net USD sales of USD 53.7 billion resulting in depletion of forex reserves; despite RBI management, rupee lost 9.5% 

Feb-Oct2022: Rupee falls by 9.5% (events described above) 

 

 

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References:

St Louis Fed: Dollar Rupee exchange rate - FRED charts 

RBI HistoryChronology of Events: From 1926 to 2003

RBIcrisis and reforms 1991 to 2000 - chronology of events - Indian rupee devaluation in 1991 / LERMS / unified exchange rate

RBIpress release 27Feb1993 – Unified exchange rate from LERMS

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Disclosure:  I've got a vested interest in Indian stocks and other investments. It's safe to assume I've interest in the financial instruments / products discussed, if any.
 
Disclaimer: The analysis and opinion provided here are only for information purposes and should not be construed as investment advice. Investors should consult their own financial advisers before making any investments. The author is a CFA Charterholder with a vested interest in financial markets.

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Tuesday, 9 December 2025

NSE's Backtesting Claims Child Indices Beat Parent Indices – But Does It Hold in the Real World?

NSE's Backtesting Claims Child Indices Beat Parent Indices – But Does It Hold in the Real World? 09Dec2025



 
 

(The views expressed here are for information purposes only and should not be construed as a recommendation or investment advice. While the author is a CFA Charterholder with nearly 25 years of experience in financial markets, this content is intended to share general insights and does not constitute financial guidance. Please consult your financial adviser before taking any investment decision. Safe to assume the author has a vested interest in stocks / investments discussed if any.)


 

1 Investor Interest in Smart Beta Indices and Passive Funds

In recent years, there has been a growing interest among investors in India in smart beta indices and the passive funds that track them. 

With the rise of smart beta strategies, there is now an increasing focus on alternative index strategies that aim to outperform traditional benchmarks by using factors such as value, size, momentum, quality and volatility.

Smart beta indices are designed to provide a systematic way to capture specific factors that have historically delivered higher returns than traditional market-capitalisation-weighted indices. As a result, both index funds and exchange-traded funds (ETFs) tracking these smart beta indices have seen a surge in popularity. 

These funds allow investors to gain exposure to these factor-based strategies without having to pick individual stocks, making it an attractive option for both retail and institutional investors. 

 

(article continues below)

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Nifty Midcap 150 Quality 50 Index: Has Quality Lost Its Edge? 10Aug2025

Decoding the Nifty Midcap 150 Quality 50: A Midcap Strategy Built on Fundamentals 07Aug2025 

Passive Titans of India: The Top 10 Equity Indices by Fund Size 17Jul2025

India Flagship ETFs with Low Fees and Fair Trading Volumes 12Jun2025 
 
Low Expense Ratios, High Returns: Why Passive Equity Funds Matter 06Jun2025 
 
How to Buy Nifty Midcap 150 Index (passive funds) 03May2024

Analysis of Nifty 100 Low Volatility 30 Index 12Sep2023

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2 What Are Parent and Child Indices?

In the context of smart beta and traditional market indices, "parent indices" refer to the broad-based market indices, such as the Nifty 50, BSE 500 or Nifty Midcap 150, which represent the entire market or a large portion of it. The parent indices are typically weighted by market capitalisation, meaning that the larger companies have a bigger influence on the index’s performance. 

The "child indices," on the other hand, are subsets or variations of these parent indices. Child indices are often constructed by applying specific filters or rules, such as selecting stocks based on a particular factor like low volatility or high dividend yield. Essentially, child indices are a way to segment the broader market to target specific investment characteristics and / or risk exposures.

For instance, the Nifty Midcap 150 might be considered a parent index, and a child index could be something like the Nifty Midcap 150 Momentum 50 Index, which includes the 50 most momentum stocks from the Nifty Midcap 150 universe. In this case, the parent index represents the entire midcap stock market, while the child index focuses on a specific subset based on momentum.

Chart showing select Nifty indices of Parent versus Child Indices >

 


3 Do Child Indices Outperform Parent Indices in Practice?

The NSE Indices Ltd claims that, based on their backtesting of historical data, child indices most of the time outperform parent indices. NSE Indices Ltd is the index provider of Nifty indices. 

The premise behind this assertion is that child indices, by focusing on specific factors like low volatility, momentum, high dividends or value can outperform the broader market index over time.

In theory, this makes sense. If the underlying factors in a child index are systematically designed to exploit inefficiencies in the market, then they may provide higher returns than the broader market. 

For example, low-volatility stocks tend to experience less dramatic price swings, which might help mitigate losses during market downturns, potentially leading to better risk-adjusted returns.

However, while this theory may hold in some cases, the real-world performance of these child indices can be more complex. In practice, the performance of child indices often depends on the specific factors they target and how those factors perform in various market cycles.



4 Examining Funds Tracking Smart Beta Indices

(Note: In a previous blog on factor investing / smart beta investing last month, I thoroughly examined whether select "smart beta" indices outperform broad based indices, like, Nifty 50 and Nifty Midcap. In the current blog, the attempt is to find out whether funds tracking smart beta child indices outperform their respective funds tracking parent indices)

To get a clearer picture of whether child indices really do outperform parent indices, it’s useful to look at some of the funds that track these smart beta strategies.

For example, consider a fund that tracks a low-volatility index (a child index) and compare it to a fund that tracks a broader market index like the Nifty 50. Over short periods, it’s possible that the low-volatility strategy could outperform the broader market, especially during periods of high market volatility. 

Conversely, during strong bull markets, the low-volatility strategy might underperform as it tends to underweight higher-growth, more volatile stocks.

Similarly, funds tracking momentum indices—child indices that emphasize stocks with strong medium term performance—could outperform in a trending market, where momentum plays a significant role. 

On the other hand, during periods of market stagnation or reversal, momentum-based strategies might underperform as the stocks driving the index may see sharp declines.

Let us see whether some of the smart beta funds have outperformed their parent indices in practice:

Example 1: Comparing the performance of index funds (tracking child indices), namely, Bandhan Nifty 100 Low Volatility 30, UTI Nifty 200 Momentum 30 and UTI Nifty 200 Quality 30 with Axis Nifty 100 Index fund tracking parent index Nifty 100.

(Note: In the absence of any passive funds based on Nifty 200, Nifty 100 is used as a proxy for Nifty 200 -- it may be noted the differences in actual returns between these two indices are small)

Image showing their performance >

Click on the image to view better >


This Value Research weblink can be used to track these funds in real time.

The above image shows:

> on a 1-year basis, while the Bandhan Nifty 100 Low Volatility 30 index fund outperformed its parent index fund, Axis Nifty 100 index fund; passive child funds based on Nifty 200 Momentum 30 and Nifty 200 Quality 30 failed to beat the parent index 

>  On a 2-year basis, Nifty 100 Low Volatility 30 (child) scored higher returns compared to the parent Nifty 100; while the Nifty 200 Momentum 30 (child) failed to beat the parent Nifty 100

> On a 3-year basis, both Nifty 100 Low Volatility 30 (child) Nifty 200 Momentum 30 (child) have beaten the parent index Axis Nifty 100's performance

> as stated above, volatility factor tends to outperform when markets face rough weather (Indian markets have been highly volatile in the past 15 months); while momentum factor is underperforming in the past 15 months due to loss of momentum in the market 

 

The following image from Rupee Vest shows the performance of  SBI Nifty 200 Quality 30 ETF (child) versus Nippon India ETF Nifty 100 (parent)

> On a 1-year, 2-year and 5-year basis, child index fund, SBI Nifty 200 Quality 30 fails to beat parent index fund, Nippon India ETF Nifty 100

> However, on a 3-year basis, child index outperformed parent index

 

Example 2: Comparing the performance of index funds (tracking child indices), namely, Tata Nifty Midcap 150 Momentum Index fund and DSP Nifty Midcap 150 Quality 50 index fund with parent index fund, Motilal Oswal Nifty Midcap 150 index fund >

Image showing their performance >

Click on the image to view better >



This Value Research weblink can be used to track these funds in real time.

The above image shows:

> on a 1-year, 2-year and 3-year basis, both the child index funds, Tata Nifty Midcap 150 Momentum 50 Index fund and DSP Nifty Midcap 150 Quality 50 index fund underperformed the parent index fund, Motilal Oswal Nifty Midcap 150 index fund

 

Example 3: Comparing the performance of index funds (tracking child indices), namely, Nippon India Nifty 500 Momentum 50 index fund and UTI Nifty 500 Value 50 index fund; with parent index fund, Motilal Oswal Nifty 500 index fund >

Image showing their performance >

Click on the image to view better >


This Value Research weblink can be used to track these funds in real time.

The above image shows:

> on a 1-year basis, both the child indices, Nifty 500 Momentum 50 and Nifty 500 Value 50 underperformed the parent index, Nifty 500 (as stated above, Momentum factor is faring badly in the past 15 months) -- however, value factor seems to be recovering in the past six months

> on a 2-year basis, child index Nifty 500 Value 50 outperformed parent index Nifty 500 (it may recalled Value factor has done well in 2023 and 2024, though it did poorly in 2025 and 2022)

> track record for three year returns is not available for the above child index funds 

 

Example 4: Comparing the performance of index funds (tracking child indices), namely, DSP Nifty 50 Equal Weight index fund and Nippon India Nifty 50 Value 20 index fund; with parent index fund, Nippon India Nifty 50 index fund >

Image showing their performance >

Click on the image to view better >


This Value Research weblink can be used to track these funds in real time.

The above image shows:

> on a 1-year, 2-year, 3-year, 5-year and 7-year basis, child index Nifty 50 Equal Weight index has consistently outperformed its parent index Nifty 50

> but child index Nifty 50 Value 20 has a mixed record; on a 3-year basis, it has delivered better returns compared to its parent Nifty 50 -- however, on a 1-year and 2-year basis, Nifty 50 Value 20 underperformed its parent Nifty 50 

 

Summary of the above four examples

One standout performance is the consistent outperformance of Nifty 50 Equal Weight over its parent Nifty 50; whereas factors, like, Low volatility, momentum and quality have shown varied performance depending on market conditions.

Nifty 50 Equal Weight has been doing well since 2020 outperforming Nifty 50 in every calendar year (2020-2025); though it underperformed Nifty 50 prior to 2020 (see chart below for data). 

As you know, Nifty 50 is market-cap weighted, meaning the largest companies by market cap (like HDFC Bank, Reliance Industries, ICICI Bank, Bharti Airtel and Infosys) dominate the index. The top five or 10 stocks can often make up a significant portion of the index’s overall performance.

Nifty 50 Equal Weight, on the other hand, gives the same weight to all 50 stocks, meaning no single stock has an oversized influence on the performance. This creates more balanced exposure across the index, mitigating the risk of heavy concentration in a few large-cap stocks. 

During the half-yearly rebalancing time (March and September), each stock will be adjusted to a weight of nearly 2 per cent each in the Nifty 50 Equal Weight index.  

There is no guarantee Nifty 50 Equal weight will continue to deliver superior performance versus Nifty 50. 

The Nifty 50 Equal Weight index outperformed Nifty 50 during periods when mid-cap and small-cap stocks experienced strong growth, particularly in 2024, 2023 and 2021, which were recovery years post-pandemic.

This reinforces the importance of market conditions when deciding between market-cap weighted indices and Equal Weight strategies. 

What would cause Nifty 50 Equal Weight to underperform Nifty 50? 

The Nifty 50 Equal Weight index underperforms when the market rally becomes narrow and heavily concentrated in a few mega-cap stocks. This is because the traditional Nifty 50 is dominated by its top 5-10 stocks (like Financials and certain IT/Oil & Gas heavyweights), which disproportionately drive returns during periods of market polarisation. 

Furthermore, the Nifty 50 Equal Weight's inherent value / contrarian tilt—by selling winners to rebalance—works against it when market momentum is firmly with the mega-cap stocks. Lastly, its higher exposure to relatively smaller, often more volatile, Nifty 50 constituents can also lead to deeper cuts during market corrections. 

Disclaimer: This analysis is provided for informational purposes only and should not be construed as investment advice or a recommendation. Please consult a financial advisor before making any investment decisions.

 

Calendar year returns of select "smart beta" indices versus Nifty 50 and Nifty Midcap 150 (see previous blog for more) >




5 Conclusion 

The idea that child indices can outperform parent indices is intriguing, and there is evidence to suggest that, in some market conditions, these factor-based indices can deliver superior returns. However, it’s important for investors to recognize that past performance does not guarantee future results.

In practice, child indices do not always outperform parent indices, and it’s crucial to take a holistic view of the market, including risk considerations and long-term investment objectives, when evaluating such strategies.

In India, the track record for smart beta funds and passive funds based on smart beta indices is still relatively short, with several funds having only three to five years of performance data.

While backtesting shows that child indices often outperform their parent indices, real-world performance hasn’t always lived up to these expectations.

Even the asset size of smart beta passive funds is smaller compared to passive funds based on Nifty 50 or Nifty Midcap 150 (for more, see blog on passive titans of India discussing asset size)

In practice, many smart beta funds struggle to deliver superior returns compared to traditional passive funds that track broad market indices. This discrepancy highlights the challenges of translating historical data-driven strategies into consistent real-world success.

Ultimately, the performance of child indices relative to parent indices varies depending on the market environment, time horizon and the specific factors the child indices focus on. While there are instances where child indices outperform, there are also periods when the broader market (parent indices) may perform better.

  

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References:
 

Tweet 02Mar2025 The Baloney of Smart Beta Indices

Nifty Return Profile (strategy indices) 

NSE Index dashboard monthly 

NSE Index dashboard archives 

NSE Indices Research Papers / working papers 

Nifty Indices factsheets  

Methodology document for Nifty indices, including smart beta indices 

Screenshot of returns of Nifty 50 versus Nifty 50 Equal Weight from 2000 to 2020 > source Nifty 50 Equal Weight whitepaper 24Feb2021 >


 

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