Some of America’s largest companies including Apple, Facebook, eBay, Intel, and Morgan Stanley are set to call on the US Supreme Court to strike down laws banning same-sex marriages.

A document with the names of at least 60 US firms will be submitted to the Supreme Court and is due to be released on Thursday.

Further names are expected to be added this week.

According to a draft copy obtained by Fortune, the companies argue that such laws “send an unmistakable signal that same-sex couples are in some way inferior to opposite-sex couples, a proposition that is anathema to amici’s commitment to equality and fair treatment to all.”

On 26 March, the Supreme Court is due to take up the case of whether to overturn Proposition 8, which in 2008 added a clause to the Californian constitution stating that marriage could only be recognised by the state if it were between a man and a woman.

Earlier this week, around 75 leading Republican figures also signed a briefing document urging the Supreme Court to strike down the homophobic California law.