Strategic Financial Management · Foreign Exchange Risk Management

Forex Arbitrage and Exchange Risk Regulation in India

Updated 11 October 2026 · Fact-checked

Forex arbitrage earns a risk-free profit from price differences between markets. Two-point arbitrage compares one currency pair across two centres. Three-point arbitrage compares a quoted cross rate with the rate implied by two other pairs. In India, FEMA and RBI rules allow hedging mainly against genuine exposures, through authorised dealer banks.

Understand Arbitrage and Exchange Risk Regulation in India

Arbitrage means buying cheap in one place and selling dear in another at the same moment, with no risk and no capital of your own at stake. In forex, the same currency should have one price everywhere. If it does not, dealers trade until the gap closes.

Two-point (locational) arbitrage uses one currency pair quoted differently by two banks or centres. You buy where the currency is cheaper and sell where it is dearer. Always buy at the ask (offer) rate and sell at the bid rate. The profit is the gap between the two.

Three-point (triangular) arbitrage uses three currencies. You work out the cross rate implied by two quotes and compare it with the cross rate actually quoted. If they differ, you go round the triangle, for example INR → USD → GBP → INR, and end with more rupees than you started with. If the rates are consistent, you end with the same amount and there is no arbitrage.

Regulation in India. Foreign exchange is governed by the Foreign Exchange Management Act, 1999 (FEMA). The RBI issues the directions under it. Banks licensed as authorised dealers (AD) deal in foreign exchange with customers and in the inter-bank market. Residents such as exporters and importers may generally hedge a genuine foreign currency exposure through AD banks, using forwards and other permitted products. Hedging is linked to an underlying exposure. Pure speculation in forex by residents is restricted.

The detailed limits, documents and product lists change through RBI circulars. In the exam, use the principles: underlying exposure, AD bank route, and RBI as regulator. Quote a figure only if the question gives it.

Key rules to remember

Cross rate: A/C = (A/B) × (B/C); Convention used on this page: X/Y means units of Y per 1 unit of X. So GBP/USD is dollars per pound and USD/INR is rupees per dollar. Multiply so that the common currency B cancels: GBP/INR = GBP/USD × USD/INR. Check the direction of every quote before multiplying.
Inverse of a quote: B/A = 1 ÷ (A/B); Use this when the quote is in the opposite direction to the one you need. For example, INR/USD = 1 ÷ (USD/INR).
No-arbitrage condition: Quoted cross rate = Implied cross rate; If they differ, a triangular arbitrage profit exists.
Bid and ask rule: You buy at the ask (offer) rate; you sell at the bid rate; The bank does the reverse. Bid is always lower than ask.
Two-point arbitrage profit per unit: Profit = Sell rate (bid) at dearer centre − Buy rate (ask) at cheaper centre; Multiply by the amount of foreign currency traded.
Regulatory rule: Hedge only a genuine underlying exposure, through an authorised dealer, under FEMA and RBI directions; Use as the framework for descriptive answers.

How to solve Arbitrage and Exchange Risk Regulation in India questions

Use this method for any arbitrage numerical, whether it has two centres or three currencies.

1Write all quotes in one direction, for example rupees per unit of foreign currency. Invert the quotes that are the other way round.
2Note whether bid and ask rates are given. If so, mark which rate you buy at (ask) and which you sell at (bid).
3For two-point arbitrage, find the centre where the currency is cheaper and the centre where it is dearer.
4For three-point arbitrage, compute the implied cross rate and compare it with the quoted one. If they are equal, state that no arbitrage exists.
5Choose the route that ends in a gain. Start with the home currency and move through each leg, converting step by step.
6Compute the final amount in the starting currency. Profit = final amount − starting amount.
7If asked, deduct transaction costs and state the profit per unit and in total.
8Add a one-line conclusion, and note that trading will push the rates back to parity.

Quickest way: Round-trip check

When to use it: Use it when you have three quotes and little time to decide the direction.

Take ₹1 (or a round amount like ₹83,00,000) and convert it round the triangle in one direction.
If you end with more than you started, that is the direction. If less, reverse the route.
Pick a starting amount that divides cleanly by the first quote to keep the arithmetic simple.
Write each leg on one line: amount, rate, result.

Common mistakes in Arbitrage and Exchange Risk Regulation in India

Using the wrong side of the bid-ask quote.
Students take the quote from the bank's view, not the dealer's.
Fix: You buy at the ask and sell at the bid. Write 'buy at ask' next to each leg before calculating.
Multiplying quotes without checking direction, for example GBP/USD × INR/USD.
With X/Y meaning units of Y per 1 X, GBP/USD is dollars per pound and INR/USD is dollars per rupee. Both are in dollars, so the common currency does not cancel.
Fix: Rewrite the quotes so that the second currency of the first quote is the first currency of the second quote. Here, use GBP/USD × USD/INR (or invert INR/USD to get USD/INR). The result is GBP/INR, rupees per pound.
Declaring arbitrage when quoted and implied cross rates are equal.
Students assume every question has a profit.
Fix: Compare the rates first. If equal, state no arbitrage.
Going round the triangle in the wrong direction and showing a loss.
Students do not test both routes.
Fix: If one direction gives a loss, reverse it. The other direction gives the gain.
Writing that residents may freely trade currencies for profit.
Students confuse market theory with Indian rules.
Fix: State that hedging is allowed against a genuine exposure through authorised dealers, and that speculation by residents is restricted under FEMA and RBI directions.
Giving profit in the foreign currency when asked for rupees.
Students stop at the second leg.
Fix: Complete the final conversion and state profit in the currency the question asks for.

Worked examples

Example 1

Mumbai quotes USD/INR as ₹83.40 (bid) – ₹83.50 (ask). Chennai quotes USD/INR as ₹83.60 (bid) – ₹83.70 (ask). Show how a dealer can make a risk-free gain on US$ 10,00,000 and compute the profit.

Show the solution

The dollar is cheaper in Mumbai (you can buy at ₹83.50) and dearer in Chennai (you can sell at ₹83.60).
Buy US$ 10,00,000 in Mumbai at the ask rate of ₹83.50: cost = 10,00,000 × 83.50 = ₹8,35,00,000.
Sell US$ 10,00,000 in Chennai at the bid rate of ₹83.60: receipt = 10,00,000 × 83.60 = ₹8,36,00,000.
Profit = 8,36,00,000 − 8,35,00,000 = ₹1,00,000 (₹0.10 per dollar).

Answer: Buy in Mumbai at ₹83.50 and sell in Chennai at ₹83.60. Risk-free profit is ₹1,00,000 before costs.

Example 2

A dealer has ₹83,00,000. Quotes (X/Y means units of Y per 1 X): USD/INR = ₹83.00 per US$; GBP/USD = US$ 1.2500 per £; GBP/INR = ₹104.50 per £. Check for arbitrage and find the profit, ignoring bid-ask spreads and costs.

Show the solution

Implied GBP/INR = GBP/USD × USD/INR = 1.2500 × 83.00 = ₹103.75 per £. The dollar cancels.
Quoted GBP/INR is ₹104.50, so the pound is dearer in the direct quote. Buy pounds through dollars and sell them for rupees directly.
Leg 1: ₹83,00,000 ÷ 83.00 = US$ 1,00,000.
Leg 2: US$ 1,00,000 ÷ 1.2500 = £80,000.
Leg 3: £80,000 × 104.50 = ₹83,60,000.
Profit = 83,60,000 − 83,00,000 = ₹60,000.

Answer: The implied cross rate (₹103.75) differs from the quoted rate (₹104.50). The route INR → USD → GBP → INR gives an arbitrage profit of ₹60,000 on ₹83,00,000.

Exam tips

Section A may test the cross-rate calculation or the bid-ask rule in a two-mark MCQ. Practise the cross rate until it takes under a minute.
In a 14-mark question, show every leg on a separate line with the rate used. Marks go for the route and the working.
For the regulation part, write about underlying exposure, authorised dealers, FEMA and the RBI role. Do not quote limits you are not sure of.
Always state the conclusion in one sentence: arbitrage exists or does not exist, and the profit.
Check whether the question asks for profit in rupees or in the foreign currency.

Practice questions from Foreign Exchange Risk Management

Arbitrage and Exchange Risk Regulation in India in other exams

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

CA FinalArbitrage and Forex Risk Management Policy

Arbitrage and Exchange Risk Regulation in India: frequently asked questions

How do I solve a three point arbitrage problem in SFM?

Convert all quotes to the same direction and compute the implied cross rate. Compare it with the quoted one. If they differ, convert a round amount round the triangle and find the final gain. If the result is a loss, reverse the direction.

What is the difference between two-point and three-point arbitrage?

Two-point arbitrage uses one currency pair quoted differently in two places. Three-point arbitrage uses three currencies and compares the quoted cross rate with the rate implied by the other two quotes.

Can Indian exporters and importers hedge their foreign exchange risk?

Yes. They can generally hedge a genuine foreign currency exposure through authorised dealer banks, within FEMA and the RBI directions. Hedging is tied to an underlying exposure, and speculation is restricted.

Do I use bid or ask rates in arbitrage questions?

You buy a currency at the ask rate and sell it at the bid rate. If the question gives only one rate for each pair, use it for all legs and ignore the spread.