Standard finance
Also written Standard finance theory
The traditional view of finance built on rational, self-interested investors with full information — the baseline set of assumptions that behavioural finance was developed to challenge.
In plain language
Before behavioural finance, most models started from one assumption: investors act rationally.
The workbook calls this baseline standard finance. It rests on a small set of assumptions about how investors behave. Behavioural finance exists because real investors keep breaking those assumptions. They hold concentrated portfolios instead of diversifying. They feel greed and fear instead of weighing risk and return calmly. They credit their own skill for what was really luck.
Standard finance is not wrong about everything. It is the starting point that behavioural finance builds on and corrects.
How it works
The workbook lists the assumptions of standard finance (section 14.1): investors are rational; investors are risk averse; investors are self-interested utility maximisers; investors update their beliefs as new information arrives; and investors have access to all available information.
The workbook's Table 14.1 then contrasts the two schools directly. Standard finance has economics at its core and treats decision-making as rule-driven and consistent, resting on the Efficient Market Hypothesis and a clean risk-return trade-off. Behavioural finance has psychology at its core and treats decisions as inconsistent, shaped by biases and herd behaviour.
The workbook credits Nobel laureates Daniel Kahneman (2002) and Richard Thaler (2017) with bringing behavioural finance to the forefront and attempting to integrate it with standard finance — the two named years are the only numeric figures the workbook attaches to this topic.
A worked example
Illustrative, following the workbook's own assumptions. Suresh, a standard-finance textbook investor, is offered a bet with 50% odds of a 20% gain and 50% odds of a 20% loss. Being rational and risk-averse, he weighs the near-zero expected value against his own risk tolerance and declines it consistently, every time it is offered.
Meenal, a real investor with a Rs 15,00,000 portfolio, is offered the identical bet twice in one month. The first time, still stinging from a recent Rs 40,000 loss elsewhere, she refuses far more strongly than the maths alone would justify. The second time, after a run of gains has made her feel confident, she accepts the same bet readily. Same investor, same bet, two different answers — exactly the inconsistency standard finance's rule-driven model does not predict.
Why NISM asks about it
Chapter 14 (Behavioural Finance), section 14.1 (Behavioural Finance versus Standard Finance), lists the five assumptions and Table 14.1's side-by-side comparison. Expect a question naming Kahneman or Thaler, or asking which assumption standard finance rests on.
Common exam traps
- Standard finance assumes investors are rational, risk-averse, self-interested, information-updating and fully informed — a question may test any one of these in isolation.
- Kahneman won his Nobel in 2002; Thaler in 2017 — the workbook credits both by name and year.
- Standard finance is not the same as the Efficient Market Hypothesis — the EMH is one output of standard-finance thinking, not a synonym for the whole framework.
- Behavioural finance does not claim standard finance is wrong in every case. It explains the gaps and anomalies standard finance leaves unexplained.
Check yourself
1.Anchoring bias occurs when people:
- a)Rely on pre-existing information when they make decisions
- b)Collect all available information when they make decisions
- c)Do not make use of any information when they make decisions
- d)Make forecasts about future prospects
Show the answer
Answer: (a) Rely on pre-existing information when they make decisions
Anchoring is relying heavily on pre-existing information — the anchor — so that all later information is seen in its light. The first price in a negotiation is the workbook's example.
Collecting all information (B) is the standard finance ideal, the opposite of a bias.
2.Behavioural finance differs from the standard model of finance because behavioural finance:
- a)Precludes the impact of investor psychology
- b)Includes the impact of investor psychology
- c)Accepts the Efficient Markets Hypothesis
- d)Rejects the idea of market anomalies
Show the answer
Answer: (b) Includes the impact of investor psychology
Behavioural finance has psychology at its core and studies how it influences market participants. It tries to explain anomalies standard finance cannot — so D is backwards.
Option A is the direct opposite of the definition.
Where this is taught
Free preparation for NISM Series XXI-BRelated terms
- Behavioural financeThe study of how psychology shapes the decisions of market participants, individually and in groups, and how those decisions show up as gaps and anomalies in financial markets.
- Bounded rationalityHerbert Simon's idea that people with limited time, information and processing ability settle for a satisfactory and sufficient choice — they 'satisfice' — instead of finding the optimal one.
- Prospect theoryKahneman and Tversky's 1979 theory of choice under risk: outcomes are judged as gains or losses from a reference point, and losses hurt more than equal gains please.
- Informational EfficiencyHow fully and quickly security prices reflect available information. It is what "market efficiency" usually means, as against operational efficiency, which is about transaction costs.