NISM-Series-X-B: Investment Adviser (Level 2) · Basics of Behavioural Finance

Heuristics and Mental Accounting in Behavioural Finance

Updated 11 October 2026 · Fact-checked

Heuristics are mental shortcuts that speed up decisions but can cause systematic errors. Mental accounting is treating money as separate pots by source or purpose. Framing is how the same facts, presented differently, change choices. To solve exam questions, spot the behaviour in the scenario, name the bias, and give the adviser's fix.

Understand Heuristics and Mental Accounting

Investors do not process every fact before deciding. They use heuristics, which are rules of thumb or mental shortcuts. Heuristics save time and often work well enough. But they can lead to predictable errors, which behavioural finance calls biases.

Common heuristics in exam material include representativeness (judging by how closely something resembles a stereotype, such as assuming a fund with three good years is a great fund), availability (judging likelihood by how easily examples come to mind, such as fearing a market crash after recent news coverage), anchoring (fixing on a reference number, such as the purchase price or a past 52-week high), and familiarity (preferring what you know, such as your employer's shares).

Framing means the way information is presented changes the decision, even when the facts are identical. A product described as '90% chance of keeping your capital' feels safer than one described as '10% chance of loss', though they say the same thing. Framing links to loss aversion: people react more strongly to losses than to equal gains.

Mental accounting means a person puts money into separate mental pots by source, purpose or label, and treats each pot differently. For example, someone treats a bonus or tax refund as 'free money' and spends it on a luxury, while being careful with the monthly salary. Another keeps a low-yield savings balance for a holiday while carrying an expensive loan. Rationally, money is fungible: a rupee is a rupee wherever it came from.

Mental accounting is not always harmful. Separate buckets for goals can help discipline, and advisers use goal-based buckets on purpose. The problem arises when the buckets cause poor choices, such as ignoring the total portfolio, holding losers to 'get back to even', or taking excess risk with 'house money' after gains.

Key formulas to remember

Heuristic: Heuristic = mental shortcut → fast decision → possible systematic bias; Heuristics are not always wrong. The exam tests the error they can cause.
Fungibility of money: ₹1 from any source = ₹1 from any other source; Mental accounting violates this principle in traditional finance.
Framing effect: Same facts + different presentation → different choice; Decisions change with wording (gain frame vs loss frame) even though the outcome is unchanged.
Key heuristics to match: Representativeness = resemblance; Availability = ease of recall; Anchoring = reference point; Familiarity = known is safe; Match the scenario cue to the heuristic name.

How to solve Heuristics and Mental Accounting questions

Use this method for any scenario or definition question on heuristics, framing or mental accounting.

1Read the scenario and underline what the investor did or said.
2Ask what is driving the choice: a shortcut (resemblance, recall, reference number, familiarity), the wording (framing) or separate money pots (mental accounting).
3Match the cue: 'looks like' means representativeness; 'recent news' or 'easily recalled' means availability; a fixed number such as purchase price means anchoring; 'treats money differently by source or purpose' means mental accounting.
4Check the options for similar-sounding biases and remove those that do not fit the exact cue.
5If the question asks for the adviser's response, pick the option that looks at the whole portfolio, goals and facts rather than the label or frame.
6Pick the answer and move on. Do not over-read the scenario.

Quickest way: Cue-word matching

When to use it: Use when you have under a minute for a scenario MCQ and the options are all named biases.

Find the one cue phrase in the scenario.
Link it: resemblance = representativeness, recent or vivid = availability, reference price = anchoring, money labelled by source or purpose = mental accounting, wording changes choice = framing.
Select the matching option and eliminate the rest.
For 'what should the adviser do', choose the total-portfolio, goal-based or reframing answer.

Common mistakes in Heuristics and Mental Accounting

Confusing anchoring with mental accounting when an investor holds a stock until it returns to the purchase price.
Both involve the purchase price and loss feelings.
Fix: If the focus is on a reference number, think anchoring. If the focus is on separate pots or labels for money, think mental accounting. Read which cue the question stresses.
Saying heuristics always lead to bad decisions.
Textbooks stress the errors.
Fix: Heuristics are useful shortcuts that can cause systematic errors. Avoid options with 'always' or 'never'.
Mixing up availability and representativeness.
Both rely on impressions rather than data.
Fix: Availability is about ease of recall of recent or vivid events. Representativeness is about similarity to a stereotype or pattern.
Treating framing as a change in the facts.
The two versions sound different.
Fix: In framing the underlying facts are identical. Only the presentation (gain or loss wording) differs.
Believing mental accounting is always harmful.
It is presented as a bias.
Fix: It can help discipline when used deliberately for goals. It is harmful when it makes a person ignore the whole portfolio or treat windfalls as free money.
Choosing a product-based fix when asked how an adviser should respond.
Students jump to solutions.
Fix: The usual best response is to educate the client, consider total wealth and goals, and present information in a balanced way.

Worked examples

Example 1

An investor receives a ₹2,00,000 annual bonus and spends it on an expensive holiday, though she keeps strict limits on her monthly salary spending and has a credit card balance at a high interest rate. Which behaviour does this best show?
A. Anchoring
B. Availability
C. Mental accounting
D. Representativeness

Show the solution

Underline the cue: the bonus is treated differently from salary.
The money is split into pots by source, with the bonus seen as free to spend.
Anchoring needs a reference number, availability needs recent or vivid recall, and representativeness needs resemblance to a stereotype. None of these appears.
Money is fungible, so the source should not change how it is used. This is mental accounting.

Answer: C. Mental accounting

Example 2

An adviser tells Client 1 that a fund has 'a 90% chance of preserving capital' and tells Client 2 that the same fund has 'a 10% chance of a capital loss'. Client 1 invests and Client 2 refuses. Which concept explains the different decisions, and what should the adviser do?

Show the solution

The two statements carry the same facts: 90% chance of no loss equals 10% chance of loss.
Different wording led to different choices, so this is the framing effect, helped by loss aversion in Client 2.
The adviser's duty is to avoid selective presentation.
The adviser should present both gain and loss views, show likely ranges of outcomes, and link the product to each client's risk profile and goals.

Answer: The framing effect. The adviser should present the information in a balanced way, showing both the gain and loss sides, and base the recommendation on the client's risk profile and goals.

Exam tips

Learn one cue phrase for each heuristic: resemblance, recall, reference point, familiarity, money pots, wording.
Questions are usually scenarios. Name the bias first, then check the options.
Be careful with absolute words such as 'always' in options about heuristics or mental accounting.
For adviser-response questions, prefer answers that use total portfolio, goals and balanced presentation.
Do not guess blindly. A wrong answer carries negative marking of 25% of the marks assigned to the question.

Practice questions from Basics of Behavioural Finance

Heuristics and Mental Accounting: frequently asked questions

What is a heuristic in finance?

A heuristic is a mental shortcut or rule of thumb used to make quick decisions. It saves effort and often works, but it can cause predictable errors. Examples are anchoring, availability and representativeness.

What is mental accounting with an example?

Mental accounting is treating money differently depending on its source or purpose. For example, a person spends a tax refund freely but is careful with salary, even though both are the same rupees.

What is the framing effect in investment decisions?

It is the change in a choice caused only by how information is presented. A '90% chance of keeping capital' and a '10% chance of loss' describe the same outcome but can lead to different decisions.

Is mental accounting always a bias to avoid?

No. Goal-based buckets can improve discipline. It becomes a problem when it makes investors ignore the total portfolio or treat windfalls as free money.