The Gateway offices are occupied by Citi, the global financial services group.
Selling agents CBRE say it is the largest office investment to come onto the market in Northern Ireland in the last decade.
In 2014, Ulster Bank sold most of its Titanic Quarter loans to the US hedge fund Davidson Kempner.
Such a fund will typically look to get a return on its money within a few years either through asset sales or loan refinancing.
The Gateway offices are likely to be attractive to institutional investors such as pension funds.
An office development in Belfast's Titanic Quarter has been put up for sale with a price tag of £29m.