New research from a lesbian, gay, bisexual and trans civil rights group has revealed that the vast majority of Fortune 500 companies include sexual orientation in their employment nondiscrimination policies.

Equality Forum reported that 471 (94.2%) of the 500 American corporations voluntarily include sexual orientation.

“In 2003, when Equality Forum began contacting the Fortune 500 companies, 323 (64.6%) companies explicitly provided sexual orientation protection in their workplace policies,” the group said in a statement.

“Equality Forum reached out to the CEOs, Human Resource Directors and all members of the Boards of Directors of the 177 (35.4%) companies without this protection.”

By 2004, 405 (81%) Fortune 500 companies had extended protections.

“The Fortune 500 have overwhelmingly decided that including sexual orientation is in the best corporate interest and helps communicate corporate values to the estimated $660 billion (£360bn) annual domestic GLBT consumer market,” stated Malcolm Lazin, Executive Director, Equality Forum.

Of the 30 Fortune 500 companies that are noncompliant, 13 (43.3%) are headquartered in Texas.

“When it comes to equality, Texas is a lone and tarnished star,” Mr Lazin said.

In the UK more than 400 employers are members of gay equality organisation Stonewall’s Diversity Champions programme.

Between them they employ more than four million people. Member organisations include IBM, Barclays, government departments, the British Army, the Royal Navy and the Royal Air Force.

Attempts by the US Congress to pass a federal law protecting gay, lesbian, bisexual and trans Americans from workplace discrimination fell apart earlier last year amid acrimonious claims and counter-claims over trans rights.

In November the Employment Non-Discrimination Act was passed by the House by 235 to 184.

ENDA was originally designed to make it illegal to fire, refuse to hire or promote a person based on sexual orientation or gender identity.

The decision to remove trans people from the scope of the legislation caused anger among the LGBT community in the US, with many demanding an “all or nothing” stance.

Many of the House Democrats serving their first term did not want ENDA to include protections for trans people, fearful of a backlash from conservatives.

President Bush has already indicated he would veto ENDA.

The White House expressed constitutional concerns that the proposal could “trample” religious rights.

Twelve states, plus the District of Columbia, bar employment discrimination on the basis of gender identity.

20 states include sexual orientation nondiscrimination in their workplace statutes.

According to Gallup’s May 2008 Values and Beliefs Poll, 89% of US citizens believe gays and lesbians should have equal rights in job opportunities.

Exxon Mobil is the largest of the Fortune 500 that does not specifically provide sexual orientation protection.

Democratic Presidential candidate Senator Barack Obama favours including sexual orientation in federal workplace protection laws.

His Republican opponent, Senator John McCain, opposes the bill.

“When 94% of the Fortune 500 Companies and 89% of the public support workplace equality, Congress is derelict by its failure to include GLBT citizens in federal workplace discrimination protection,” said Mr Lazin.

“There is no cost to provide sexual orientation protection. Corporations and shareholders benefit from a workplace where merit, not intolerance, prevails.”