The UK's Serious Fraud Office has agreed to pay £3m in damages to Vincent Tchenguiz after he was arrested in March 2011.
The SFO will pay a further £3m to cover Tchenguiz's legal costs.
The SFO had brought a series of cases against him and his brother in recent years, which collapsed due to lack of evidence.
SFO Director David Green said the organisation regretted its mistakes.
"I am pleased that we have been able to resolve this matter without the need for a costly trial. The SFO deeply regrets the errors for which we were criticised by the High Court in July 2012. On behalf of the SFO I apologise to Mr Tchenguiz for what happened to him," he said in an emailed statement.
The High Court ruled in 2012 that the SFO should pay Tchenguiz's costs for those public law proceedings.
Vincent Tchenguiz is an Iranian British entrepreneur. The separate civil damages case brought by Vincent's brother is yet to be settled.