Taking a stance in favour of equal marriage cost Goldman Sachs at least one client, the chief executive Lloyd Blankfein has said.

Speaking to an audience of gay rights activists yesterday, he said that taking such a political position was ‘not without a price.’ The Human Rights Campaign, a gay rights organisation, had recruited him in February to speak out for equal marriage

He added: “There was some adverse reaction by someone… They didn’t want to continue a relationship that they had with us in money management… I won’t say the name, but if you heard the name, it wouldn’t surprise you.”

The event was organised by Out on the Street, an LGBT advocacy group based in Wall Street.

Mr Blankfein also said that Wall Street was more supportive of gay rights than other industries on account of what he called “a meritocratic culture.” He added: “Wall street shouldn’t be out in front. Wall Street just is out in front.”

Another high-profile banker, Brian Moynihan, the chief executive of Bank of America also spoke at the event, despite his strong Catholic beliefs. He echoed David Cameron’s comments that conservative politics was no reason to be against equal marriage. “It’s people on the other side who sometimes want to legislate how you live your life.”

Mr Moynihan was joined by another self-described “strong right-wing conservative,” Paul Singer, the founder of Elliot Capital Management. The latter, who is believed to have donated huge amounts into pro-equality campaigns, said: “I don’t think it’s going to be a harsh environment in a Romney administration.”

Mr Singer’s comments was not particularly well-received by those who drew attention to the fact that Richard Grenell, an openly gay Republican, was effectively forced to resign as foreign policy spokesperson by religious right on account of his sexuality.