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The study uses a quadratic programming model to estimate the impacts of Bt cotton adoption on consumer benefits, cotton programme outlays, and producer returns, by state and adoption status. Three scenarios were considered, simulating low, moderate, and high impacts of Bt cotton adoption. For the moderate scenario, US benefits from Bt adoption grew from $44 million in 1996 to $66 million in 1998. Annual benefits to US cotton purchasers ranged between $46-$55 million. Benefits to Bt adopters grew from $57 million in 1996 to $97 million in 1998. Losses to non-adopters fell from -$59 million in 1996 to -$8 million in 1998 as rising commodity programme payments mitigated the impact of lower prices.