Multi-millionaire Mark Langford, ex-head of personal injury insurance firm The Accident Group (TAG), was killed in the Spanish resort of Marbella where he lived with his wife Deborah.
Langford (42) was the founder of the Manchester-based firm which collapsed in 2003 with debts of around £100m.
Revenue and Customs were pursuing Langford for unpaid tax.
TAG's employees received no redundancy money and the company was liquidated in January 2004.
Spanish police said there was no alcohol in Langford's system and they are investigating the cause of the crash.
According to reports, Langford was served with a tax demand as he prepared to host a party on board his £1.5 million yacht in southern Spain. He had been due to appear in the High Court in London several weeks ago, but the court was told he was too depressed to attend the bankruptcy hearing over a £4.1m bill.
In addition to bankruptcy proceedings, Langford was facing moves by the Department of Trade and Industry to ban him from acting as a company director.
Three other fomer TAG directors have already been disqualified - Gary Hoddes until May 2011, his brother Phil until May 2008 and Jacqui Brennan until September 2008.