The Jewish Association for Business Ethics (Jabe) has closed due to a lack of funding. It is thought four people, including executive director Lorraine Spector, lost their jobs.
The organisation was formed in 1991 and relied entirely on private funding. It encouraged integrity in professional conduct and taught Jewish ethical approaches to business.
More than 300 people attended Jabe's 20th anniversary dinner last November. But it raised only £90,000 towards the annual £330,000 operating costs.
Jabe chairman Alan Tapnack, former executive director of Investec Bank, and fellow trustees, had been covering the funding shortfall for a number of years. He said: "I put in a fortune myself but I couldn't carry on doing it. I was using up my own pension.
"Everybody loves Jabe and thinks it's valuable, but no one wants to pay for it. "
In 2006, Chief Rabbi Lord Sacks, Jabe president, vetoed the participation of non-Orthodox rabbis in the charity, prompting the resignations of leading trustees and donors, including Lord Kalms; former Leo Baeck College chairman, Gerald Rothman; and Jabe's former chairman, billionaire Stephen Rubin.