We investigate tax fraud in a major export-promotion program in India – the Duty Drawback scheme – which enables exporting firms to claim a cash rebate proportional to the value of their exports, at a product-specific drawback rate. We detect fraud based on two approaches. First, we show that bilateral trade asymmetries between reported exports by India and reported imports by trading partners of the same trade flows are systematically correlated with the rate of drawback, suggesting that exporting firms over-report exports to unduly gain duty drawback. Second, we find evidence of excess bunching in the distribution of unit values reported by India at kinks in the per-unit drawback schedule, relative to the distribution of unit values reported by importing countries. Our results suggest that fraud currently detected by customs represents only 3.8%–6% of actual fraud.