The bank on Monday said it would buy Lehman Brothers' former office at Canary Wharf for £495m to use as its new European investment banking headquarters
Jamie Dimon, chief executive, is understood to have a held a series of meetings with Mr Osborne, culminating in a dinner in New York last week at which the matter was discussed.
The acquisitions are a significant boost for London after concerns Mr Dimon wanted to focus investment elsewhere due to anger about UK tax and regulation
However, one source with knowledge of the discussions said Mr Osborne and Mr Dimon had developed a "good dialogue".
Doubts remain over a planned 1.9m sq ft Riverside South development at Canary Wharf that had been earmarked as JP Morgan's European base. The bank has asked Canary Wharf Group to proceed with construction to street level, but JP Morgan only said in a statement on Monday that the site would be developed for "future use".