Overnight Indexed Swap in India: OIS Pricing and Uses (IIBF)

The overnight indexed swap in India is the most heavily traded rupee interest rate derivative, and it is the contract IIBF reaches for when it wants to test whether you truly understand interest rate risk. Master the idea that one leg pays a fixed rate while the other simply compounds an overnight benchmark, and most other rupee derivatives fall into place behind it.

This guide walks you from the plumbing of the two legs, through the Mumbai Interbank Outright Rate that feeds the floating side, to pricing, central clearing at CCIL and the Reserve Bank rules a bank treasury must respect. Read it alongside the derivative market chapter in your Treasury Management syllabus.

🔁 What an Interest Rate Swap Is and Why OIS Dominates

An interest rate swap is a bilateral contract in which two counterparties agree to exchange interest cash flows on an agreed notional principal for an agreed term. One party pays a fixed rate. The other pays a floating rate that resets against a published benchmark. Only interest flows move; the notional is a computation base, never a loan.

What distinguishes the overnight indexed swap in India from other swap structures is the choice of floating benchmark. Instead of a term rate fixed once per period, the floating leg accrues the overnight benchmark day by day and compounds it geometrically across the calculation period. Each day's rate is applied to the previous day's accreted balance, so the floating leg ends up as the realised compounded cost of rolling overnight money for the whole tenor.

For tenors up to one year the market convention is a single net exchange at maturity: the two legs are computed, netted, and one payment moves. For longer tenors the swap pays annually. The day count on both legs is Actual/365. Because only the net difference changes hands, the cash intensity of the contract is tiny relative to the notional it hedges.

That efficiency is exactly why the structure won. It references a transparent, transaction-based overnight rate rather than a polled term rate, it is cheap to clear, and it tracks the policy rate closely enough to be the natural hedging tool for a bank funding itself in the call and repo markets.

💡 Exam Tip: The notional principal is never exchanged. Credit exposure on a swap is therefore limited to the replacement cost — the cost of re-entering an equivalent contract if your counterparty defaults — not the notional.

📊 The MIBOR Benchmark, Tenors and Where Liquidity Sits

The floating leg of the overnight indexed swap in India references the overnight Mumbai Interbank Outright Rate (MIBOR), administered by Financial Benchmarks India Pvt Ltd (FBIL). FBIL computes it from actual call money transactions executed on the NDS-CALL platform in the opening window of the trading day, which makes it a transaction-based benchmark rather than a submission-based one — a distinction examiners like.

Benchmark reform has not stopped there. Following the Reserve Bank's review of the MIBOR benchmark, work has been under way on a secured overnight rupee rate drawn from the far deeper market repo and TREPS segments, to sit alongside or eventually succeed the unsecured overnight rate. Expect questions on the rationale: a secured rate rests on a much larger daily transaction volume and is harder to distort.

Standard tenors run from one month out to five years, but activity is not evenly spread. The one-year and five-year points carry the bulk of the volume because they line up with the horizons dealers actually care about — the policy cycle and the medium-term funding book. Off-the-run points such as two or three years trade, but with wider bid-offer spreads.

🛡️ How a Bank Treasury Actually Uses OIS

There are three classic uses, and IIBF tests all three. The first is hedging. If your bank has a liability whose cost floats with the overnight rate, you are exposed to rates rising. Paying fixed and receiving floating on the overnight indexed swap in India converts that liability into a synthetic fixed-rate borrowing: the floating you receive offsets the floating you pay, and your net cost becomes the swap's fixed rate.

The mirror image applies to a fixed-rate asset funded at floating rates. Here the treasury receives fixed and pays floating only if it wants to keep the floating exposure; more commonly it pays fixed to lock the funding cost against the fixed coupon it is earning. The same logic drives duration management on the investment book, which is why the swap sits so close to the material in the fixed income securities, duration and convexity chapter.

The second use is expressing a view. A dealer who believes the policy rate will be cut faster than the market has priced will receive fixed, profiting if the realised compounded overnight rate undershoots the fixed rate agreed today. This is a trading position, not a hedge, and it must sit inside the trading book limits framework alongside the bank's net open position limit and other board-approved caps.

The third use is synthetic funding. A treasury that can raise cheap floating money but wants fixed-rate stability — or the reverse — uses the swap to transform the profile without disturbing the underlying borrowing. This interlocks directly with the treasury and ALM interface, because the swap changes the repricing buckets in the gap statement, not the balance sheet size.

⚠️ Common Mistake: Candidates write that "paying fixed protects against falling rates." It is the other way round. You pay fixed to protect against rates rising; you receive fixed to benefit if rates fall.

📈 Reading the OIS Curve and Its Spread over G-Secs

Because the floating leg is the compounded overnight rate, the fixed rate on a swap of a given tenor is, in effect, the market's average expectation of the overnight rate over that tenor. String those fixed rates together and you have the OIS curve — the cleanest publicly observable read on where the market thinks the policy rate is heading.

An upward-sloping curve says the market expects tightening or a term premium for uncertainty; an inverted curve says it expects cuts. Analysts routinely compare the one-year point against the current policy rate to infer how many basis points of easing or tightening are priced in over the next four quarters. This is why the overnight indexed swap in India is read as a forecasting instrument and not merely a hedging one.

The spread between the government securities yield and the swap rate of the same tenor carries separate information. Government paper embeds sovereign funding supply, statutory demand from SLR requirements and the state of banking-system liquidity. The swap rate embeds none of those directly — it is a pure expectations-plus-credit construct settled on an overnight index. A widening spread therefore usually points to a supply shock in bonds or a funding squeeze, rather than a change in the expected policy path. Learn to separate the two signals and you can answer any curve interpretation question the examiner sets.

For the underlying market structure behind both curves, revisit the financial market chapter and keep the current policy rates in front of you from the RBI rates reference page.

⚖️ Valuation, CCIL Clearing and the RBI Rulebook

Valuation is discounted cash flow, done twice. The fixed leg is a known schedule of payments discounted on the OIS discount curve. The floating leg is projected from the same curve — the forward overnight rates implied by it — and discounted identically. The swap's mark to market is the difference between the two present values, positive to whichever side the market has moved in favour of. At inception the fixed rate is set so the two present values are equal and the swap is worth zero.

Daily revaluation feeds the bank's profit and loss and its margin obligations. For the mechanics of how banks strike and book these values, see our note on mark to market valuation of derivatives, and for the parallel treatment on the investment book see mark to market valuation of investments.

Most rupee swaps are novated to the Clearing Corporation of India, which becomes the central counterparty to both sides. CCIL collects initial margin against potential future exposure and exchanges variation margin daily to settle the change in mark to market, so bilateral credit exposure is replaced by exposure to a qualifying central counterparty — which attracts a far lighter capital charge than an uncleared bilateral trade.

The governing framework is the Reserve Bank's Master Direction on Rupee Interest Rate Derivatives, which classifies participants as retail or non-retail users. Retail users may transact only to hedge an underlying exposure; non-retail users may take positions for any purpose within their own risk limits. Verify the latest amendments directly on the RBI Master Directions page. On accounting, trading swaps are marked to market through P&L while swaps designated as hedges follow accrual treatment mirroring the hedged item, and counterparty exposure is measured as current mark to market plus a potential future exposure add-on for capital and exposure-norm purposes.

📌 Remember: Central clearing does not remove market risk from the overnight indexed swap in India. It converts counterparty credit risk into margin and liquidity risk — you must fund variation margin in cash, every day, whichever way the curve moves.

Tie this back to the desk structure and control environment in the integrated treasury chapter before you attempt the mocks.

🧠 Practice MCQs: Overnight Indexed Swap

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❓ Frequently Asked Questions

🎯 Conclusion: Turn This Into Marks

If you can draw the two legs, name FBIL as the benchmark administrator, state that the notional never moves, explain why paying fixed hedges a floating liability, and describe how CCIL substitutes margin for counterparty risk, you have covered nearly every angle IIBF sets on the overnight indexed swap in India. Add the curve interpretation and the spread-over-G-secs argument and you can handle the descriptive questions too.

Now convert the reading into recall. Work the tenor table until the conventions are automatic, then attempt a timed set. Browse more Treasury Management explainers on the Treasury Management tag hub, or jump straight into a CAIIB course and take a full-length chapter test today.