Toby Whittaker, whose Dylan Harvey Residential business collapsed last year owing creditors £6.5m, was attacked by a masked gang at his home in Lancashire on Thursday night.
Whittaker, 32, was beaten up and his family threatened when six men burst into their £1.5m home in Read, near Blackburn.
The armed robbers forced his wife and their four children to hide under a dining table while he was assaulted before the gang fled with jewellery. The gang used Whittaker's £60,000 Audi Q7 4×4 car for their getaway.
Police said the investigation into the raid would include examining whether former business associates or creditors may be behind the attack.