Support for gay marriage by companies as varied as Goldman Sachs, Microsoft and Starbucks is gathering steam to change policies in American states that bar same-sex couples from tying the knot. Two US Supreme Court decisions on June 26 heartened supporters of the cause while showing an increased willingness by business to back the effort. In one case, more than 200 companies signed a brief against a federal law that denied benefits to same-sex couples. Five years ago, only a handful had lobbied against California's Proposition 8 ban on same-sex marriages, the target of the high court's other decision. State legislators stand to feel the heat as more businesses speak out against laws in states including Texas, Florida and Michigan that recognise only heterosexual marriage. While fewer than half the companies in the Standard & Poor's 500 are based in states that allow gays to wed, most already have policies that ban discrimination based on sexual orientation. "Companies do have the choice where they locate, where they set up shop," said Kellie McElhaney, founding faculty director of the Centre for Responsible Business at the University of California, Berkeley. Local policies on sexual orientation would "eventually become part of the choice process", she said. Goldman Sachs and Expedia are among businesses gearing up to support a federal bill to prevent workforce discrimination based on sexual orientation. Of Fortune 500 companies, 88 per cent include sexual orientation in their non-discrimination policies and more than 60 per cent offer domestic partner health benefits, according to the Human Rights Campaign, a Washington-based NGO. "We thrive as an organisation because we embrace that diversity - diversity of opinion, of orientation, of race," Expedia chief executive Dara Khosrowshahi said. Companies started providing health benefits for same-sex couples and adopting non-discrimination rules in the 1990s, just as Congress went in the opposite direction to approve the federal government's rejection of gay marriage in the 1996 Defence of Marriage Act. Now, said Edith Hunt, Goldman Sachs's chief diversity officer, corporate America was pushing for uniform laws that protected against workplace discrimination. "Now you can be fired in some places just for being gay or lesbian, and that seems totally unacceptable to us," Hunt said last week. "The firm has long embraced a wide array of diversity activities and issues. There's really a very strong business case around it." Kevin Johns, who heads the economic development office for the city of Austin, in Texas, can attest to how a more liberal stance on social issues can help lure companies. Johns makes trips to California, New York and Chicago to tout Austin's support of domestic-partner benefits and its tolerant attitude towards sexual orientation, even though it's the capital city of a state whose governor, Rick Perry, is an outspoken conservative. Austin has reeled in investment from Apple, eBay and IBM. "We're trying to attract the most creative, smartest people regardless of their orientation, colour, sex or anything," Johns said. "It's been very successful." States that have authorised same-sex marriage have jumped to 13 from none at the beginning of 2004, and others, such as New Jersey, are debating legislation for approval. Of the states that bar gay unions, 29 have the ban written in their constitutions. The federal law made it difficult to treat all employees equally, interfered with diversity efforts and caused "significant" costs, said Brad Smith, Microsoft's executive vice-president for legal and corporate affairs. Starbucks spokesman Zack Huston said: "Equality and inclusion are core values of our company."