EMS Capital, a New York-based shareholder in Canary Wharf owner Songbird Estates, has said it plans to accept the Qatar Investment Authority's (QIA) £2.6bn ($4.08bn, €3.29bn) hostile offer for the UK property firm.
EMS Capital is the holder of some 4% of Songbird's share capital.
EMS's backing has brought total shareholder support to about 32% of Songbird's free float, QIA and its bidding partner, US investor Brookfield Property Partners, said in a statement.
"Taken together with the letter of intention from Madison International Realty announced on 8 December, QIA and Brookfield have so far received public support from holders of approximately 31.6% of Songbird's free float," the statement said.
Earlier, another Songbird shareholder, Third Avenue Management, also backed the bid.
Songbird has said it would look into the final bid in more detail and is carefully considering its full response.
The offer was launched to Songbird shareholders on 4 December.
London's Canary Wharf business district has a complex ownership structure with two layers of shareholders: one in an unlisted company called the Canary Wharf Group and the other in London-traded Songbird Estates.
The Canary Wharf Group is majority owned by Songbird, with a 69.4% stake. Brookfield is the second largest shareholder in the unlisted firm with a 22.1% stake.
Songbird's shareholders include the QIA, with a 28.6% stake, Simon Glick, a 56-year-old New York investor with a near 26% stake and China's sovereign wealth fund that holds a 15.8% stake.