Sky News has learnt that Hotcourses, a listings service set up by Mr Hunt and his business partner Mike Elms in 1996, is expected to announce this week that it has been sold for between £30m and £35m.
A deal was said by a legal source to be close to being signed on Sunday evening.
Filings at Companies House suggest that Mr Hunt owns approximately 48% of the shares in Hotcourses, meaning a takeover worth £35m would yield a payday for the cabinet minister worth £16.8m.
The latest register of MPs' interests says only that he holds more than 15% of the business.
The prospective buyer of Hotcourses, which recently set up an international advisory group to accelerate its overseas expansion, is understood to be an Australasian company with operations in the education sector.
It is not the first time that Mr Hunt has closed in on a big windfall from Hotcourses' sale.