Efficient Market Hypothesis
Also written EMH · Efficient Market Hypothesis (EMH)
The proposition that share prices already incorporate and reflect all relevant information — which, if true, leaves nothing for an analyst to find by studying that information.
In plain language
If every fact about a company is already in its price, then the price is the answer and there is no gap between price and value to exploit. That is the Efficient Market Hypothesis, and it is the idea against which the entire research analyst profession defines itself.
The workbook does not endorse it. It introduces EMH precisely to say that fundamental analysis contradicts it: profits come from identifying a good investment and buying it at the right price, which presupposes that the price is sometimes wrong.
How it works
The workbook states EMH twice, in two chapters, and the two statements point in opposite directions.
In Chapter 4.4, having explained that an investor should buy below intrinsic value and sell above it, it says this thought process is in contradiction of the Efficient Market Hypothesis, which propagates that share prices incorporate and reflect all relevant information.
In Chapter 15.3.1, setting out the first tenet of Dow Theory — the market discounts everything — it says that tenet aligns with the Efficient Market Hypothesis and is foundational to technical analysis, which assumes price action reflects all relevant data.
So the same hypothesis is presented as the enemy of fundamental analysis and the friend of technical analysis. Read strictly, that cannot hold: a market that has already absorbed all relevant information has absorbed the information contained in past prices too, which would leave the chartist no better placed than the fundamental analyst. The workbook's third position, in Chapter 4.6, is the behavioural one — that prices move away from fair value, up and down, because of the fear and greed of market participants.
Answer whichever chapter the question comes from.
A worked example
Put the hypothesis to work on a decision an Indian investor actually faces.
A large-cap active fund charges a total expense ratio of 1.8%. An index fund tracking the same benchmark charges 0.20%. The benchmark itself returns 12% a year before costs.
If EMH holds, the active manager cannot systematically find mispricing, so gross alpha is zero and each investor simply receives the benchmark less costs:
Active fund net return = 12.0 − 1.8 = 10.2%
Index fund net return = 12.0 − 0.2 = 11.8%
On Rs 10 lakh invested for 15 years:
Active : 10,00,000 × 1.102^15 = Rs 42.92 lakh
Index : 10,00,000 × 1.118^15 = Rs 53.27 lakh
Gap = Rs 10.35 lakh
The gap is larger than the original investment. That Rs 10.35 lakh is the hurdle the active manager must clear before the investor is a rupee better off — which is the practical content of the hypothesis, and also why the workbook sets active and passive investing out as a genuine choice in Chapter 4.1 rather than declaring a winner.
Why NISM asks about it
Chapter 4 (section 4.4) introduces EMH as the proposition fundamental analysis contradicts, and Chapter 15 (section 15.3.1) links it to the first tenet of Dow Theory. Expect a definitional question — prices incorporate and reflect all relevant information — and a question on the relationship between EMH and fundamental analysis, where the workbook's answer is contradiction.
Common exam traps
- The workbook takes both positions. Chapter 4.4: fundamental analysis contradicts EMH. Chapter 15.3.1: the "market discounts everything" tenet aligns with EMH and is foundational to technical analysis. Quote the chapter the question is drawn from.
- EMH says information is in the price, not that the price is right. It is not a claim that markets never fall or that valuations are always sensible.
- Chapter 4.6 sets out the opposite view, that prices leave fair value because of fear and greed. The workbook does not resolve the conflict, and neither should an exam answer.
- EMH is not an argument that research is pointless. Chapter 4.2 spends its length on how much work getting good information takes — which is what an efficient market would have to have already absorbed.
- Mosaic analysis is the analyst's legitimate response (Chapter 4.2.1): assembling individually insignificant public and non-public pieces into an insight. Acting on a single piece of unpublished price sensitive information is not.
- Do not read EMH as a recommendation of passive investing. Chapter 4.1 presents active and passive as two approaches with different objectives, not a verdict.
Check yourself
1.The fundamental analyst's thought process — that price can diverge significantly from fair value, creating a profit-making opportunity — is described in the workbook as:
- a)A direct application of the Efficient Market Hypothesis
- b)In contradiction of the Efficient Market Hypothesis
- c)Unrelated to the Efficient Market Hypothesis
- d)A special case of the Efficient Market Hypothesis that applies only to small-cap stocks
Show the answer
Answer: (b) In contradiction of the Efficient Market Hypothesis
The workbook says this thought process is in contradiction of Efficient Market Hypothesis (EMH), which propagates that share prices incorporate and reflect all relevant information.
The logic is worth holding on to. If EMH were fully true, price would always equal fair value, there would be no divergence to exploit, and estimating intrinsic value would be pointless. Fundamental analysis only earns its keep because prices can be wrong.
Option A inverts the relationship. Option C is wrong because the workbook explicitly links them. Option D invents a size-based carve-out found nowhere in the text.
Where this is taught
Free preparation for NISM Series XVRelated terms
- Fundamental analysisEstimating what a share is worth from the profits and cash flows the business will generate, then buying only when the market price sits below that estimate.
- Intrinsic valueWhat an asset is actually worth — the present value of the cash it will generate over its remaining life, as against whatever price the market is quoting today.
- Margin of safetyThe gap between a security's estimated intrinsic value and the lower price paid for it — the cushion that protects the buyer when the estimate turns out to be wrong.
- Technical analysisForecasting price direction from past price and volume alone, on the assumption that everything worth knowing about a company is already in its price.
- Unpublished price sensitive informationInformation about a company or its securities that is not generally available and that would, on becoming available, be likely to materially affect the price of the security.