Two brothers scammed people out of their pensions to fund a millionaire lifestyle, buying cars and a boat.
Alan Taylor, 38, of St Stephen's Road, Norwich, and Russell Taylor, 37, of Trunch Road, Mundesley, admitted the £17m fraud at Norwich Crown Court.
The pair persuaded 239 pensioners to invest with their companies, gaining access to their pension funds.
They invested the money in high-risk schemes, pocketing any profit and passing on losses to the client.
Both pleaded guilty to conspiracy to defraud and will be sentenced next month.
An investigation by Norfolk Police found the two had stolen vast sums of money between 2008 and 2015.
They used their company Taylor and Taylor Associates based in Norfolk to persuade clients to invest with them.
Without their knowledge, the brothers transferred the money to another company they owned, Vantage Investment Group Ltd and placed it in a high-risk finance scheme.
"It was a win-win situation for the two men - if the investments paid off they would take 20% of the profits, and any losses were effectively funded by the client," said a spokeswoman for the Eastern Region Special Operations Unit (ERSOU).
On average each client lost almost half of their total pension fund and an investigation was launched in 2015 when several pensioners became concerned about their losses.
Det Ch Insp Liz Fernandes, from ERSOU, said: "All this was for their own personal gain.
"The Taylor brothers greatly abused the trust their clients had in them and invested their hard-earned money into a high-risk investment scheme akin to a roulette wheel," Ms Fernandes said.
"One victim unknowingly invested £200,000 in the scheme and was left with just over half of that amount," said Anamarie Coomansingh from the Crown Prosecution Service.
She added some pensioners were forced to "take up part-time jobs to help them through retirement as a result of the impact on their finances".