Microsoft, Amazon, Costco and Nordstrom are among the companies behind an ad endorsing passage of Referendum 74, the November 6 referendum which asks voters to uphold – or reject – a gay marriage law approved by lawmakers.

The ad first appeared in Sunday's Seattle Times, according to an HRC blog post.

As leaders who do business in Washington State, our companies and organizations strive to attract the best and the brightest talent in order to compete in a global marketplace and to reflect our communities, customers and employees’ diversity. We are endorsing Referendum 74 to uphold the state's civil marriage equality law that allows all loving, committed couples to be married, while also protecting religious freedom,” the ad states.

“We support allowing all loving, committed couples the freedom to marry because it means every employee is treated fairly, it helps our competitive business advantage and is good for our state's economy.”

Executives from REI and Alaska Airlines also added their names to the ad.

Amazon CEO Jeff Bezos earlier this year gave $2.5 million to the campaign working to approve Referendum 74.