Out of an estimated 900,000 people working in London's Square Mile, some 55,000 are gay or lesbian and this number is growing as the stigma over homosexuality in the City wanes.
A study by consultancies Joslin Rowe Associates and Origin HR, both part of the Blomfield Group, found the City over the past two years has become a much less inhospitable environment for gay and lesbian employees.
A study over the past two years of 20,392 candidates for City roles, which collated information on sexuality for diversity monitoring purposes, found that, two years ago, 5.9 per cent of respondents anonymously identified themselves as gay or lesbian.
But in the past 12 months this figure had risen to 6.3 per cent as legislative changes and a diversity drive in the financial services industry had encouraged more applicants.
Tara Ricks, managing director of Joslin Rowe Associates, said: "Traditionally the City was perceived as white, heterosexual and male Ė which put off gay and lesbian applicants.
"Times have changed and diversity is now a major watchword. The City knows it must attract the best talent from all walks of life and from around the world. Many firms now actively target gay undergraduates, for example, something that was not the case five or ten years ago," she added.
Keith Robinson, managing director of Origin HR, said that all the major investment banks now had gay networking groups.
Across the industry, organisations such as Out in the City, the Interbank Gay & Lesbian Network and City Pink (which targets women only) provided opportunities for gay and lesbian employees to meet and mix.
"None of this existed five years ago. What's more, investment banks now come top of Stonewall's Corporate Equality Index as the best place to work for homosexual employees. Indeed, three of the top ten organisations in the country are investment banks," he added.
Yet there was still some way to go, the survey also found. There was room for another 35,000 gay or lesbian employees before the industry matched the mix in London's general population.
Furthermore, the extent to which people were "out" in their firms was far smaller than the number who privately acknowledged they were homosexual.
Arguably, City workers were more likely to keep their own counsel than those in other industries, such as the media with a traditionally more open attitude.
This was particularly so for women. In Joslin Rowe's research, women in the City were far less likely to identify themselves (even anonymously) than men as homosexual.
Robinson said: "Of course there is no reason why people should disclose their sexuality at work. It is irrelevant to their ability to do the job.
"The City has made huge strides in recent years, but is still a challenging and competitive place to work.
"The reluctance of women to come out as lesbians possibly reflects the fact that women already feel they have to fight hard to maintain equality with men," he added.