The National Institutes of Health stopped the worldwide Moderate Alcohol and Cardiovascular Health (MACH) trial in 2018 because of institutional failings that led to the biased design of this major study. Drawing on e-mail correspondence among officials, researchers, and alcohol companies, we provide the first, to our knowledge, detailed analysis of alcohol industry involvement in the MACH trial.Alcohol companies agreed to fund the MACH trial to advance their commercial interests rather than to help answer a major scientific question. Alcohol industry executives seized opportunities presented by discussions of the MACH trial to try to influence this study and wider public health, research, and policy decision-making.The process of soliciting research funding from corporations, which included convincing alcohol companies that the study design supported their commercial interests, was intrinsically biased. Thus, the three parties-research funding officials, researchers, and industry executives-coproduced the biased trial design. A detailed understanding of this episode will be helpful in advancing efforts to protect public health research from biases associated with corporate donations.