Ex-Conservative Party deputy chairman Lord Ashcroft says he will start donating to the party again.
The tycoon told the BBC he would probably join a club for party donors called the Leader's Group.
This club requires an annual membership fee of £50,000.
Lord Ashcroft - also a former party treasurer - donated millions of pounds to the Conservatives, often targeted at marginal seats, but fell out with ex-prime minister David Cameron in 2010.
Speaking to BBC political editor Laura Kuenssberg, the peer praised Mr Cameron's replacement, Theresa May, for her speech on Brexit to the Conservative conference on Sunday.
Asked whether he would be prepared to donate again, he said: "I think, probably, I might join the Leader's Group again but that's a small sum compared to historically what I have given to the party."
The Leader's Group is described as the Conservative Party's "premier supporter group".
Members are invited to join the prime minister and other senior figures at dinners, drinks receptions and other events, in exchange for their annual £50,000 donation.
Lord Ashcroft, who was ranked 74 in the 2015 Sunday Times Rich List, said he hoped that under Mrs May the party would have "significantly broadened" its funding base so it was not dependent on individuals giving "seven-figure sums".
Asked whether he would be prepared to donate smaller sums, he replied: "Under the appropriate circumstances and the direction in which it's heading, it's very nice to be back."
Lord Ashcroft was deputy chairman of the Conservative Party during Mr Cameron's period as Leader of the Opposition.
In July 2010, he gave up his non-domiciled tax status after a law was passed requiring peers and MPs to be tax resident and domiciled in order to remain in Parliament.
His tax status had long been criticised by his opponents.
When he co-authored a book on Mr Cameron last year, he admitted to having personal "beef" with the prime minister after not being offered a major job in the coalition government following the 2010 general election.
He has been credited with helping to rescue the party's finances in the past, once stepping in to personally guarantee its overdraft when it was reportedly £3m in the red.