Free Money Day is observed worldwide every September 15. This social experiment, launched in 2011 by the Post Growth Institute, promotes economics based on sharing. The date was chosen to commemorate the 2008 bankruptcy filing of Lehman Brothers, the largest in U.S. history. On this day, individuals are encouraged to give money to strangers in public places, typically in the form of two coins or bills, with the request that one be passed on to someone else. Participants may also engage in creative methods of giving, such as coffee shop owners providing free coffee while asking customers to donate an equivalent amount to a stranger. The amount of money given is at the discretion of the participants, who are also encouraged to interact with those they help.