The founder of Amazon.com and his wife are donating $2.5m (£1.6m) to defend a gay marriage law passed in the US state of Washington.
Jeff and MacKenzie Bezos are the latest wealthy backers, joining Microsoft CEO Steve Ballmer and co-founder Bill Gates, who each gave $100,000.
Washington is one of four states facing a November referendum on gay marriage.
The law, due to come into effect on 7 June, was put on hold after a petition to vote on Referendum 74 succeeded.
Opponents gathered more than 240,000 signatures in a bid to overturn the law signed in February by Governor Chris Gregoire.
Same-sex marriage is legal in eight US states and the District of Columbia.
The laws are being challenged in Washington and Maryland. The state of Maine is voting to reinstate gay marriage laws that were passed but later overturned, and Minnesota is considering a constitutional ban on gay marriage.
Notwithstanding my somewhat of a ‘call-to-arms’ to my fellow Christians in my last post, this is the difficulty: just about all of big business, exemplified by the likes of Google, Amazon, and Microsoft, is getting behind the progressive zeitgeist, which may eventually make it very difficult for Christians to avoid doing business with those who stand for values to which we do not adhere; I don’t tend to get involved in boycotts myself, partly for this reason. But maybe it is nevertheless time for us to take a stand, regardless of the costs…