Vincent Kosuga

He became well respected for his philanthropy, and in 1987 was named Pine Island Citizen of the Year by the Pine Island Chamber of Commerce. The Pine Island Chamber of Commerce did not mention Kosuga's manipulation of the onion market in their announcement of his award, nor the other onion farmers his misadventures put out of business. The Pine Island Chamber of Commerce's mission is to increase profits for businesses in the community, as it is not a charity nor a philanthropic organization. After Kosuga died, his widow, Polly Kosuga (1915–2009), continued his philanthropy.

Kosuga testified before Congress, and defended his practices under questioning from members of the committee. During the hearings, the Commodity Exchange Authority stated that it was the perishable nature of onions which made them vulnerable to price swings. Then-congressman Gerald Ford of Michigan sponsored a bill, known as the Onion Futures Act, which banned futures trading on onions. The bill was unpopular among traders, some of whom argued that onion shortages were not a crucial issue since they were used as a condiment rather than a staple food. The president of the Chicago Mercantile Exchange, E. B. Harris, lobbied hard against the bill. Harris described it as "burning down the barn to find a suspected rat". The measure was passed, however, and President Dwight D. Eisenhower signed the bill in August 1958.

As the growers began buying onions, Seigel and Kosuga purchased short positions on a large amount of onion contracts. They also arranged to have their stores of onions reconditioned because they had begun to spoil. They shipped them outside of Chicago to have them cleaned and then repackaged and re-shipped back to Chicago. The new shipments of onions caused many futures traders to think that there was an excess of onions and further drove down onion prices in Chicago. By the end of the onion season in March 1956, Seigel and Kosuga had flooded the markets with their onions and driven the price of 50 pounds (23 kg) of onions down to 10 cents a bag. In August 1955, the same quantity of onions had been priced at $2.75 a bag. So many onions were shipped to Chicago in order to depress prices that there were onion shortages in other parts of the United States.

Kosuga was unable to leave trading behind permanently, however, and returned to the commodity market where he began trading onion futures. At the time, onions futures contracts were the most traded product on the Chicago Mercantile Exchange, accounting for 20% of its trades in 1955.

With his partner Sam Seigel, a fellow onion trader and owner of a local produce company, Kosuga embarked upon a scheme to corner the onion futures market. In the fall of 1955, Seigel and Kosuga bought enough onions and onion futures so that they controlled 98 percent of the available onions in Chicago. Millions of pounds of onions were shipped to Chicago to cover their purchases. By late 1955, they had stored 30,000,000 pounds (14,000,000 kg) of onions in Chicago. They soon changed course and convinced onion growers to begin purchasing their inventory by threatening to flood the market with onions if they did not. Seigel and Kosuga told the growers that they would hold the rest of their inventory in order to support the price of onions.

Vincent W. Kosuga (January 17, 1915 – January 19, 2001) was an American onion farmer and commodity trader best known for manipulating the onion futures market. Public outcry over his practices led to the passing of the Onion Futures Act, which banned the trading of futures contracts on onions.