Quintain sold a 60% stake in Greenwich Peninsula Regeneration Ltd last year to a Hong Kong based Knight Dragon for £175m gross.
Including £50m instalments still to be paid on the first deal, Quintain will get £230m in aggregate, realising a profit after tax of £34.6m on the deal.
Knight Dragon is owned by Dr Henry Cheng Kar-Shun, chairman of New World Development, a £4.6bn Hong Kong listed conglomerate with substantial interests in property and infrastructure in Hong Kong and China.
Quintain chief executive Maxwell James said: "This is a compelling transaction for Quintain which, on attractive terms, delivers financial stability and certainty for our shareholders by crystallising future profits and cash flows at an early stage. The deal reflects the step change in value created at Greenwich Peninsula since the formation of our joint venture with Knight Dragon last year.
"We have now completed Quintain's wider corporate repositioning, paving the way for a new phase of profitable growth for Quintain. We can now accelerate our major commercial and residential scheme at Wembley Park, building on this month's opening of the London Designer Outlet and, with a strengthened financial position, Quintain's highly experienced London team is well positioned to exploit new opportunities investing in selected income and value creating assets in the key London markets."