In 2007 he co-founded and became a non-executive director of Social Finance UK, a London-based advisory organisation that has worked to create a social investment market in the UK. The organisation provides access to capital, designs social finance interventions and offers advice to investors and social sector entities interested in delivering significant social impact. It has developed the social impact bond which is a financial instrument that is an outcomes-based contract in which public sector commissioners commit to pay for significant improvement in social outcomes for a defined population. Social Finance set up a pilot social impact bond with the Ministry of Justice (MoJ) in September 2010 to reduce re-offending amongst male prisoners leaving HMP Peterborough who have served a sentence of less than 12 months. During the Peterborough Prison pilot, experienced social sector organisations, such as St. Giles Trust and the Ormiston Children and Families Trust, provided intensive support to 3,000 short-term prisoners over a six-year period, both inside prison and after release, to help them resettle into the community. In July 2017, the success of the Peterborough Social Impact Bond was announced. The results showed reoffending of short-sentenced offenders reduced by 9% overall compared to a national control group. This exceeded the target of 7.5% set by the Ministry of Justice. As a result, the 17 investors in the Peterborough Social Impact Bond receive a single payment representing their initial capital plus an amount that will represent a return of just over 3% per annum for the period of investment. Cohen is also a member of the board of directors for Social Finance UK's sister organisation in the United States, Social Finance US.