Sky News understands that negotiations between Inflexion Private Equity and Hotcourses, a provider of online education listings, broke down in recent weeks.
The talks are not expected to be resumed with Inflexion and it is not thought that Hotcourses is in active discussions with another party, although a sale remains on the cards at some point, an insider said.
A deal would have catapulted the Health Secretary to the top of the Cabinet Rich List.
Mr Hunt is understood to own 49% of Hotcourses, meaning that his shareholding would be worth just over £17m if the takeover is completed.
People close to the talks said Inflexion and Mike Elms, who co-founded the business with Mr Hunt, had disagreed about a number of aspects of the deal.
Hotcourses was set up in 1996 by the two men to provide listings information about evening, training, university and other courses.
Now employing more than 200 people, Mr Hunt established the business when he returned to the UK after two years in Japan teaching English and learning Japanese.
It now claims to be the world’s largest course database, advertising more than 700,000 courses and 33,995 scholarships from more than 27,000 institutions.
According to accounts filed at Companies House for the six months to July 31, 2012, the company had a turnover of £6.5m, generating pre-tax profits during the period of just under £2m.
The Health Secretary has received several million pounds in dividends since Hotcourses was founded.
An aide to Mr Hunt said in November, when Sky News revealed the talks with Inflexion, that he was not playing any role in the sale negotiations.
The latest Register of MPs’ Interests confirms that the Health Secretary remains an investor in Hotcourses but does not disclose the size of his interest.
The company’s website says that Mr Hunt “stepped aside from all management responsibilities at Hotcourses Ltd in order to focus on his parliamentary duties, and is no longer involved in the running of the company”.
An Inflexion spokesman declined to comment on Tuesday.