RBI FX curbs opened an arbitrage bankers won’t touch
Recent RBI‑linked foreign‑exchange curbs created price distortions between exchange‑traded rupee futures and onshore forwards, which technically opened an arbitrage, but bankers avoided exploiting it because of regulatory risk. That hesitation underlines the need for treasuries and advisers to quickly interpret regulation changes and redesign hedging policies when market structure shifts. (thehindubusinessline.com)
On March 27, 2026, the Reserve Bank of India told banks to shrink their rupee foreign-exchange exposure in the onshore deliverable market to no more than $100 million by the end of each business day, with compliance due by April 10. That looked like a technical order aimed at calming a falling currency. It quickly turned into something traders could see on their screens: banks rushed to unwind old positions, dollars were sold in the forward market, and prices that normally move together started to split apart (rbi.org.in, thehindubusinessline.com, thehindubusinessline.com). By April 7, that split was large enough to create an apparent arbitrage between two versions of the same basic bet on the rupee. The April exchange-traded dollar-rupee futures contract was quoted near 93.4850, while the comparable onshore forward rate was around 93.25, according to market participants cited by Reuters. In calmer times, a bank would usually try to lock in that gap by buying the cheaper leg and selling the richer one, then wait for the prices to converge as expiry approached (thehindubusinessline.com). The catch is that these were not normal times. The same RBI move that opened the gap also made banks afraid to touch it. Bank treasuries had just been forced out of what had been treated as low-risk arbitrage books, and several were already nursing losses from the unwind. One senior treasury official told Reuters that after the RBI’s actions, the focus had narrowed to “managing flows and positions,” not putting on fresh trades that might later be judged too clever by a regulator still trying to squeeze speculation out of the market (thehindubusinessline.com, thehindubusinessline.com). To see why, it helps to picture the plumbing. A forward is an over-the-counter contract a bank writes directly with another bank or a client. A futures contract is traded on an exchange. Both point to where the market thinks the rupee will be at a future date, so their prices usually stay close because dealers arbitrage away any large difference. But RBI’s limit hit the deliverable market first, and the forced selling there pushed forward rates down faster than exchange futures could adjust (thehindubusinessline.com, thehindubusinessline.com). The disruption spread beyond that one trade. Reuters reported that the one-year forward implied yield briefly jumped to 3.96% on March 30 before easing to around 3.35%, up from 2.90% before the curbs. CCIL’s April 7 data still showed unusually jumpy forward pricing across tenors, with the near-month contract moving in wide intraday ranges instead of the tidy increments treasurers prefer (thehindubusinessline.com, ccilindia.com). Then the RBI tightened the screws again. On April 1 it revised its rules on risk management and inter-bank dealings, and bankers said the central bank also barred banks from offering rupee non-deliverable forwards to resident and non-resident clients, cutting off one more route that had helped the market absorb mispricing. Reuters estimated that banks had built $30 billion to $40 billion of arbitrage exposure, and only about half to 60% had been unwound early in the process, leaving laggards to exit at worse prices (rbi.org.in, thehindubusinessline.com). For a CA student thinking about treasury consulting, this is the useful part of the story: the trade was visible, but the real constraint was not mathematics. It was permission. Banks were trying to infer the regulator’s intent in real time, while corporates were simultaneously being told they could no longer cancel and rebook forward contracts that had drifted from hedges into directional bets. When market structure changes that fast, the winning adviser is the one who can redraw hedge policy, trading limits, client documentation, and escalation rules before the next dealing room call starts (economictimes.indiatimes.com, rbi.org.in). In the end, the most revealing number was not the futures-forward spread. It was the $100 million cap sitting in a circular on the RBI website, small enough to force some of the biggest banks in the market to stare at an open arbitrage and leave it alone (rbi.org.in, thehindubusinessline.com).
