A letter posted to the Human Rights Campaign blog on Wednesday, signed by CEOs and executives representing 42 tech companies across the United States, urged legislators around the country to update their states' civil rights laws in the wake of Indiana's Religious Freedom Restoration Act.

The letter's co-signers included the CEOs of Twitter, eBay, Lyft, Airbnb, Square, about.me, Tumblr, and Evernote, along with high-ranking executives at Cisco, YCombinator, and Zynga. It also included the signatures of Salesforce CEO Mark Benioff and Yelp CEO Jeremy Stoppelman, both of whom had already written open letters emphatically opposing the RFRA, but it did not include a signature from Apple CEO Tim Cook, who had already written a similar call to other states' legislatures over the weekend in a Washington Post op-ed.

"We believe it is critically important to speak out about proposed bills and existing laws that would put the rights of minorities at risk," Affirm CEO Max Levchin wrote in the co-signed letter. "The transparent and open economy of the future depends on it, and the values of this great nation are at stake."

While the letter didn't call out any state or law in particular, its introduction mentioned "a host of anti-LGBT bills pending or signed in to law in states around the country."

The letter noted that over 20 US states are "considering" bills similar to the one Indiana Governor Mike Pence signed into law last week and condemned how those laws could restrict access to jobs, services, and housing. "We call on all legislatures to add sexual orientation and gender identity as protected classes to their civil rights laws and to explicitly forbid discrimination or denial of services to anyone," the letter concluded.

The letter was published shortly after Arkansas Governor Asa Hutchinson vetoed a bill with the same name in his own state; upon vetoing it on Wednesday, Hutchinson asked that state's legislature to rewrite the law so that it "mirrors the federal religious act" with anti-discriminatory protections written into it.