Periodic Gap and Cumulative Mismatch Calculations - Article

Introduction

The Structural Liquidity Statement (SLS) helps a bank identify when liquidity will be available and when it will be required.

Cash inflows and cash outflows are placed into prescribed maturity buckets. The bank then calculates:

1. the Periodic Gap for each individual bucket; and

2. the Cumulative Mismatch after combining that bucket with all earlier buckets.

These two figures answer different questions.

The Periodic Gap shows the liquidity surplus or shortage within one particular time bucket.

The Cumulative Mismatch shows the bank’s running liquidity position up to that point in time.

Under RBI’s current Commercial Banks – Asset Liability Management Directions, 2025, the SLS is used to track cash-flow mismatches and measure future liquidity surplus or deficit. RBI particularly monitors cumulative negative mismatches in the first 30 days.

Liquidity Management is part of Module D of the 2026 CAIIB BFM syllabus, which specifically includes measurement and management of liquidity risk.

Learning Objectives

After studying this topic, you should be able to:

• calculate the Periodic Gap for each liquidity time bucket;

• calculate cumulative inflows, outflows and cumulative mismatch;

• distinguish an individual negative gap from a cumulative negative mismatch;

• calculate the regulatory mismatch percentage correctly;

• apply RBI’s current 5%-10%-15%-20% short-term limits; and

• identify common calculation and interpretation errors in CAIIB numericals.

Start with Cash Inflows and Cash Outflows

Every SLS calculation begins by separating future cash flows into:

Cash Inflows

Examples include:

• loan repayments;

• interest receipts expected to be realised;

• maturing investments;

• inter-bank placements maturing;

• securities-sale proceeds;

• receivables from financial transactions; and

• other expected cash receipts.

Cash Outflows

Examples include:

• deposit withdrawals and maturities;

• repayment of borrowings;

• committed loan disbursements;

• payment obligations;

• expected drawdown of commitments;

• crystallisation of contingent liabilities; and

• other expected payments.

RBI requires these cash flows to be placed into time buckets based on their residual maturity or projected future behaviour.

Periodic Gap

The Periodic Gap measures the liquidity position within one specific maturity bucket.

Periodic Gap = Cash Inflows − Cash Outflows

A positive figure indicates a liquidity surplus in that bucket. A negative figure indicates a liquidity deficit.

Refer to the Formula Section for a detailed explanation, variables, and solved examples.

Interpretation

The sign is important.

If inflows are ₹X and outflows are ₹Y:

• if X > Y → positive gap;

• if X = Y → zero gap;

• if X < Y → negative gap.

Important Point

A negative Periodic Gap does not automatically mean an RBI mismatch-limit breach.

The current regulatory short-term limits are expressed in terms of net cumulative negative mismatch, not merely the individual periodic gap.

Cumulative Cash Inflows and Outflows

To calculate cumulative mismatch, first build running totals.

Cumulative Cash Inflows = Sum of Cash Inflows from the First Bucket up to the Relevant Bucket

This shows all inflows expected up to the selected horizon.

Refer to the Formula Section for a detailed explanation, variables, and solved examples.

Similarly:

Cumulative Cash Outflows = Sum of Cash Outflows from the First Bucket up to the Relevant Bucket

This shows all outflows expected up to the selected horizon.

Refer to the Formula Section for a detailed explanation, variables, and solved examples.

The word cumulative means that earlier buckets are not forgotten.

For example, while analysing the 8–14-day position, the bank considers cash flows from:

• Next Day;

• 2–7 days; and

• 8–14 days.

Cumulative Mismatch

The Cumulative Mismatch is the running total of liquidity surpluses and deficits.

Cumulative Mismatch = Cumulative Cash Inflows − Cumulative Cash Outflows

This identifies the bank’s overall liquidity surplus or deficit up to the relevant time horizon.

Refer to the Formula Section for a detailed explanation, variables, and solved examples.

The same result can also be obtained as:

Current Cumulative Mismatch = Previous Cumulative Mismatch + Current Periodic Gap

This is useful when a maturity-ladder table already provides Periodic Gaps.

Refer to the Formula Section for a detailed explanation, variables, and solved examples.

Why Periodic and Cumulative Gaps Can Tell Different Stories

Consider the logic of successive buckets.

Negative Periodic Gap but Positive Cumulative Position

A bank may have accumulated a large liquidity surplus in earlier buckets.

The current bucket may show:

Inflows < Outflows

and therefore a negative Periodic Gap.

However, the earlier surplus may be large enough for the Cumulative Mismatch to remain positive.

Therefore:

Negative Periodic Gap ≠ Automatically Negative Cumulative Mismatch

Positive Periodic Gap but Negative Cumulative Position

The reverse is also possible.

The bank may have accumulated a large deficit in earlier buckets.

The current bucket produces a positive Periodic Gap, but the new surplus may be insufficient to eliminate the earlier deficit.

Therefore:

Positive Periodic Gap ≠ Automatically Positive Cumulative Mismatch

This is a common CAIIB numerical trap.

Working Table for Gap Calculations

A convenient calculation format is:

The best examination technique is to complete the table column by column rather than performing all calculations mentally.

Regulatory Cumulative Negative Mismatch Percentage

If the Cumulative Mismatch is negative, calculate its size relative to cumulative cash outflows.

Cumulative Negative Mismatch % = Absolute Value of Negative Cumulative Mismatch ÷ Cumulative Cash Outflows × 100

This measures the cumulative liquidity deficit relative to the cumulative obligations falling within that horizon.

Refer to the Formula Section for a detailed explanation, variables, and solved examples.

The use of the absolute value is simply to express the size of the deficit as a positive percentage when comparing it with the regulatory limit.

For example conceptually:

• cumulative mismatch = negative;

• take the magnitude of that deficit;

• divide by cumulative cash outflows;

• multiply by 100;

• compare with the applicable RBI limit.

Current RBI Short-Term Mismatch Limits

Under the Reserve Bank of India (Commercial Banks – Asset Liability Management) Directions, 2025, the net cumulative negative mismatch must not exceed the following percentages of cumulative cash outflows:

These limits apply to the specified domestic and overseas SLS and are also adopted for consolidated bank operations under the current framework.

RBI requires banks to monitor cumulative mismatches across all time buckets through internal prudential limits approved by the Board or Risk Management Committee, while the regulatory focus is particularly strong on mismatches up to 30 days.

Easy Pattern

The limits rise in steps:

5 → 10 → 15 → 20

as the horizon moves through:

Next Day → 7 Days → 14 Days → 30 Days

How to Test Compliance

For each of the first four buckets, use the following sequence.

Step 1: Calculate the Periodic Gap

Subtract outflows from inflows for that bucket.

Step 2: Calculate Cumulative Inflows

Add current inflows to all earlier inflows.

Step 3: Calculate Cumulative Outflows

Add current outflows to all earlier outflows.

Step 4: Calculate Cumulative Mismatch

Subtract cumulative outflows from cumulative inflows.

Step 5: Check the Sign

If the cumulative mismatch is positive, there is no net cumulative negative mismatch for that horizon.

If it is negative, proceed to the percentage test.

Step 6: Calculate Negative Mismatch Percentage

Divide the magnitude of the negative cumulative mismatch by cumulative cash outflows.

Step 7: Compare with the Relevant RBI Ceiling

Compare against:

• 5%;

• 10%;

• 15%; or

• 20%

according to the maturity bucket.

Maximum Permissible Negative Mismatch

Another useful way to approach a numerical is to calculate the maximum permitted deficit first.

Maximum Permissible Negative Mismatch = Cumulative Cash Outflows × Applicable RBI Limit

This calculates the maximum regulatory negative cumulative gap for the relevant short-term bucket.

Refer to the Formula Section for a detailed explanation, variables, and solved examples.

Then compare:

Actual Negative Cumulative Mismatch vs Maximum Permissible Negative Mismatch

If actual deficit exceeds the permitted amount, the applicable mismatch limit has been breached.

This method can be easier when the question asks:

“What is the maximum permissible negative mismatch?”

rather than asking for the percentage.

Current Time Buckets

The current commercial-bank maturity disclosure framework uses:

1. Day 1;

2. 2–7 days;

3. 8–14 days;

4. 15–30 days;

5. 31 days to 2 months;

6. over 2 months to 3 months;

7. over 3 months to 6 months;

8. over 6 months to 1 year;

9. over 1 year to 3 years;

10. over 3 years to 5 years; and

11. over 5 years.

For this numerical subtopic, the first four buckets are especially important because RBI specifies explicit cumulative negative-mismatch limits for them.

Cumulative Mismatch Is a Running Total

One of the easiest ways to avoid mistakes is to imagine a bank carrying forward its previous liquidity position.

If Bucket 1 ends with a deficit, Bucket 2 begins conceptually with that deficit still needing to be absorbed.

If Bucket 2 provides a surplus, that surplus reduces the earlier deficit.

This creates the running relationship:

Previous Cumulative Position + Current Periodic Position = New Cumulative Position

A learner should never calculate a cumulative mismatch using only the current bucket’s figures.

Interpretation of a Regulatory Breach

Suppose a calculation produces a cumulative negative mismatch percentage above the permitted limit.

It means the bank’s expected short-term funding deficit is larger than the regulatory tolerance for that horizon.

Management may need to:

• raise additional short-term funding;

• mobilise deposits;

• repo or sell liquid securities;

• reduce near-term funding concentrations;

• reschedule future balance-sheet growth where feasible;

• increase liquidity buffers; or

• otherwise modify the asset-liability profile.

The purpose of the limit is therefore not merely arithmetic.

It provides an early warning of excessive short-term liquidity pressure.

Gap Calculation and Behavioural Assumptions

Correct arithmetic cannot compensate for incorrect cash-flow slotting.

RBI requires cash flows to be placed according to residual maturity or projected future behaviour of:

• assets;

• liabilities; and

• off-balance-sheet items.

Therefore, before calculating gaps, the bank must correctly determine when the cash flow is expected.

For example:

• stable portions of deposits may behave differently from their legal withdrawal terms;

• loans can be prepaid;

• committed limits may be drawn; and

• contingent liabilities may crystallise.

A numerical question may therefore test both:

1. correct bucketing, and

2. correct gap calculation.

Practical Banking Application

Suppose ALCO receives an SLS showing:

• a deficit in the Next Day bucket;

• another deficit in the 2–7-day bucket;

• a surplus in 8–14 days; and

• a larger surplus in 15–30 days.

Management should not simply conclude:

“Later surpluses are large, so liquidity is satisfactory.”

It must calculate the cumulative position at every prescribed horizon.

An early deficit may breach the 5% or 10% limit even though the cumulative position becomes comfortable later.

This is the central purpose of cumulative mismatch analysis:

Later liquidity cannot automatically solve a funding obligation that falls due earlier.

CAIIB Exam Focus

1. Gap Means Inflows Minus Outflows

Keep the sign convention consistent.

2. Negative Gap Means a Deficit

Do not reverse the interpretation.

3. Periodic Gap and Cumulative Gap Are Different

Periodic relates to one bucket.

Cumulative includes the current and all previous buckets.

4. RBI Limits Apply to Net Cumulative Negative Mismatch

Do not compare only the Periodic Gap with the regulatory percentage.

5. Denominator Is Cumulative Cash Outflows

This is one of the most important numerical points.

6. Use the Absolute Size of a Negative Gap for Percentage Comparison

The minus sign indicates deficit; the percentage measures its magnitude.

7. Remember 5–10–15–20

These correspond to:

Next Day → 2–7 → 8–14 → 15–30 days.

8. Earlier Surplus Carries Forward

It can absorb a later Periodic Deficit.

9. Earlier Deficit Also Carries Forward

A later Periodic Surplus may reduce it without eliminating it.

10. Correct Bucketing Comes Before Correct Arithmetic

A perfectly calculated figure can still be wrong if cash flows were placed in the wrong maturity bucket.

Common Exam Traps

Trap 1: Subtracting Inflows from Outflows

If the working convention is Inflows − Outflows, reversing the subtraction also reverses surplus and deficit.

Trap 2: Treating a Negative Periodic Gap as a Regulatory Breach

Wrong. RBI’s prescribed short-term limits relate to the net cumulative negative mismatch.

Trap 3: Calculating Each Cumulative Gap Independently from Only Current-Bucket Figures

Wrong. All earlier cash flows must be carried forward.

Trap 4: Dividing by Periodic Cash Outflows

Wrong for the regulatory cumulative mismatch test. Use cumulative cash outflows.

Trap 5: Using Cumulative Inflows as the Denominator

Wrong. RBI specifies cumulative cash outflows.

Trap 6: Comparing Every Bucket with 20%

Wrong. The first four limits are 5%, 10%, 15% and 20% respectively.

Trap 7: Ignoring a Positive Earlier Gap

Wrong. Previous liquidity surplus affects the current cumulative position.

Trap 8: Ignoring an Earlier Deficit after a Positive Current Gap

Wrong. The current surplus must first absorb the accumulated deficit.

Trap 9: Using 15–28 Days from Older Material

For the current commercial-bank framework, use the 15–30-day bucket.

Memory Technique

Use:

I − O = P

• I = Inflows

• O = Outflows

• P = Periodic Gap

Then:

Previous Cumulative + P = New Cumulative

Finally, if the cumulative figure is negative:

Deficit ÷ Cumulative Outflows × 100

For regulatory limits, remember:

5 – 10 – 15 – 20

The full numerical sequence is:

Bucket → Inflows → Outflows → Periodic Gap → Cumulative Gap → Mismatch % → RBI Limit