International Olympic Committee rules state that candidate cities cannot make a prior agreement to give paid work to businesses that advise for free at the bid stage if they later win the Games. But all four firms should be in a good position to get an instruction should London win.
Clifford Chance’s US office has donated between $10,000 (£5,400) and $50,000 to New York’s campaign. The firm has 77 partners in New York and 230 in London, while Freshfields has 180 in London and 14 in New York.
Freshfields donated the money alongside a group of other law firms put together by Morgan Stanley.
The vast majority of corporate sponsors have stuck to just a single city, although French national champion EDF is supporting both the London and Paris bids, while Accenture is supporting London and New York.