FRM Exam Part II · Fundamental Review of the Trading Book

Trading Book vs Banking Book Boundary under FRTB

Updated 11 October 2026 · Fact-checked

The boundary decides which capital rules apply to an instrument. Under FRTB, instruments held for trading go to the trading book (market risk capital). A presumptive list sets default assignments, and supervisors must approve exceptions. Reclassifying after inception is generally barred, except in extraordinary circumstances, and any capital benefit is removed by a capital add-on.

Understand Trading Book vs Banking Book Boundary

Every bank splits its positions into two books. The trading book holds positions held with trading intent or to hedge other trading book positions. They are marked to market and charged market risk capital. The banking book holds positions held to collect cash flows or for longer-term purposes. They are charged credit risk capital, and interest rate risk is handled separately (IRRBB).

The split matters because capital differs. Before FRTB, the boundary rested on trading intent, which is subjective. Banks could move positions to the book with the lower charge. The intent-based boundary under Basel 2 and 2.5 allowed capital arbitrage between books, which the Fundamental Review of the Trading Book sought to curb.

FRTB makes the boundary more objective. It still starts from trading intent, but adds a presumptive list of instruments presumed to be in the trading book unless the bank gets supervisory approval to treat them otherwise. Examples include instruments held as market-making positions, instruments held to benefit from short-term price movements, and instruments that create a net short credit or equity position in the banking book.

The two lists work differently. The trading book presumptive list is rebuttable: a bank can depart from it only with supervisory approval, and the bank bears the burden of proof. The banking book list is mandatory: unlisted equity, real estate holdings, retail and SME credit, and equity investments in funds that cannot be looked through or for which no daily price is available must be in the banking book. Trading intent cannot override it, and there is no exception route. Supervisors can also require a bank to move a position if it does not match the rules.

Reclassification is tightly restricted. Banks should not move positions after initial designation, except in extraordinary circumstances approved by the supervisor and publicly disclosed. If a switch is allowed and lowers total capital, the difference is imposed as a disclosed capital add-on so the bank gains no benefit. The add-on is the capital before the switch minus the capital after it, measured at the time of the switch. It is then held constant and runs off as the relevant positions mature.

Key formulas to remember

Default assignment rule: Instrument on the mandatory banking book list → banking book, whatever the intent; otherwise trading intent or hedge of a trading position → trading book; otherwise → banking book; The mandatory banking book list covers unlisted equity, real estate, retail and SME credit, and equity investments in funds that cannot be looked through or lack daily prices. Trading intent cannot override it, and there is no exception route. Presumptive trading book list items go to the trading book unless the supervisor approves an exception.
Reclassification add-on: Add-on = max(0, Capital before switch − Capital after switch); Applies only when a switch reduces total capital. It is the capital difference measured at the time of the switch, held constant (not recomputed) and it runs off as the relevant positions mature. If the switch does not reduce capital, the add-on is zero.
Reclassification trigger: Switch only if extraordinary circumstances AND supervisor approval AND public disclosure; All three conditions are needed. Changes in market conditions or in accounting or tax treatment alone do not qualify.

How to solve Trading Book vs Banking Book Boundary questions

Use this order for any boundary or reclassification question.

1Identify the instrument and the stated purpose: market making, short-term gain, hedging, or hold to collect cash flows.
2Check the lists: is the instrument on the presumptive trading book list or on the mandatory banking book list?
3If it is on the presumptive trading book list, apply the default. Check whether the bank has supervisory approval for an exception and whether it can document it. If it is on the mandatory banking book list, assign it to the banking book. There is no exception route.
4If the question is about reclassification, test for extraordinary circumstances, supervisor approval and public disclosure.
5If a switch is allowed, compute capital before and after and take the add-on as any capital reduction.
6State the resulting capital regime: market risk (standardised or internal models approach) or credit risk plus IRRBB.
7Pick the answer that matches the rule exactly, not the one that sounds most flexible.

Quickest way: Three-question screen

When to use it: Use for multiple-choice questions with a short scenario and four plausible answers.

Ask 1: Is this a trading intent or hedge of a trading position? If yes, trading book.
Ask 2: Is it on the presumptive list? If yes, the default holds unless the supervisor approves otherwise.
Ask 3: Is it a switch after inception? If yes, treat as barred unless extraordinary, approved and disclosed, and apply the add-on if capital falls.
Eliminate any option that lets the bank decide alone or keeps the capital saving.

Common mistakes in Trading Book vs Banking Book Boundary

Saying the bank may freely reclassify when its business strategy changes.
Students think intent is flexible, as it was before FRTB.
Fix: Remember that reclassification is allowed only in extraordinary circumstances, with supervisor approval and public disclosure.
Treating the presumptive list as absolute with no exceptions.
The word presumptive is read as mandatory.
Fix: The list is a rebuttable presumption. A bank can seek an exception with supervisory approval and must bear the burden of proof.
Letting the bank keep the capital reduction after a switch.
Students forget the add-on is designed to remove the benefit.
Fix: If a switch lowers capital, hold the difference as an add-on. If it raises capital, no reduction applies and the higher requirement stands.
Assuming accounting treatment decides the book.
Fair value accounting is mistaken for trading intent.
Fix: The boundary is a regulatory classification. Accounting and tax changes alone do not justify a switch.
Putting all equity positions in the banking book because they are long-term.
Holding horizon is confused with purpose.
Fix: Equity held for trading, market making, or as a net short position goes to the trading book. Unlisted equity, real estate, and equity investments in funds that cannot be looked through or lack daily prices must be in the banking book.

Worked examples

Example 1

A bank moves a corporate bond position from the trading book to the banking book six months after purchase, citing weak market liquidity. Market risk capital was USD 12 million. Credit risk capital in the banking book would be USD 8 million. The supervisor has not approved. What is the FRTB result?

Show the solution

Weak market liquidity is not an extraordinary circumstance that justifies a switch by itself.
No supervisory approval or public disclosure exists, so the switch is not permitted.
The bond remains in the trading book at USD 12 million market risk capital.
Because the switch is not permitted, no add-on is computed. The USD 8 million banking book figure plays no part in the result.

Answer: The reclassification is not allowed. The position stays in the trading book with USD 12 million market risk capital.

Example 2

A bank approved for an extraordinary reclassification moves a position from the banking book (capital USD 5 million) to the trading book (capital USD 9 million). What add-on applies and what total capital must the bank hold for the position?

Show the solution

Add-on = max(0, capital before − capital after) = max(0, 5 − 9) = 0.
The switch increases capital, so the bank gains no benefit and no add-on is needed.
Capital is the trading book requirement of USD 9 million.

Answer: The add-on is zero, and the bank holds USD 9 million for the position.

Exam tips

Questions often hinge on one word: extraordinary, presumptive, approval or disclosure. Read for it.
If an option says the bank may reclassify at its own discretion, it is almost certainly wrong.
Know both directions: the add-on only matters when the switch reduces capital.
Link the boundary to capital: trading book means market risk capital, banking book means credit risk plus IRRBB.
Watch for scenario items on net short banking book positions, which go to the trading book.

Practice questions from Fundamental Review of the Trading Book

Trading Book vs Banking Book Boundary in other exams

The same ground in other exams, if you are preparing for more than one or want another angle on it.

Trading Book vs Banking Book Boundary: frequently asked questions

What is the FRTB presumptive list?

It is a list of instruments that must be assigned to the trading book by default, such as market-making positions and positions held for short-term gain. A bank can depart from it only with supervisory approval and must justify the exception.

Can a bank reclassify between books under FRTB?

Only in extraordinary circumstances, with supervisor approval and public disclosure. Market movements, accounting changes or tax changes alone do not qualify.

What is the capital add-on for reclassification?

It is the capital reduction gained from the switch, held as extra capital so the bank gets no benefit. It is zero if the switch raises capital.

Why did Basel change the boundary?

The old intent-based test under Basel 2 and 2.5 allowed capital arbitrage between books. FRTB makes the boundary more objective and harder to game.