Airbnb’s founders are not alone in speaking out against the president’s decision.

Tech leaders have a vested interest in immigration issues, of course. The industry has long poured money and resources into defending the H-1B visa program, which allows companies to recruit skilled workers from other countries.

High-profile executives including Amazon CEO Jeff Bezos, YouTube CEO Susan Wojcicki, Google CEO Sundar Pichai, and Microsoft CEO Satya Nadella have made statements urging Congress to protect DACA. More than 500 entrepreneurs and business leaders have signed an open letter in support of the program.

Apple’s Tim Cook issued an “urgent plea” to leaders in Washington “to protect the Dreamers so their futures can never be put at risk in this way again.” (Two-hundred of Apple’s employees are Dreamers.) Facebook’s Mark Zuckerberg called on Congress to “to pass the bipartisan Dream Act or another legislative solution that gives Dreamers a pathway to citizenship.”

Get Data Sheet, Fortune’s technology newsletter.

Both DACA and H-1B policies are reminders of the sizable role immigrants play in Silicon Valley. Fifty-one percent of billion-dollar startups in the U.S. were founded by immigrant entrepreneurs. In turn, those companies create an average of roughly 760 jobs per company. In 2016, 40.2% of firms on the Fortune 500 list had at least one founder who either immigrated to the United States or was the child of immigrants. Those firms generated more than $4.8 trillion in revenue in 2014 and employed 18.9 million people globally.

So yes, there’s a reason DACA specifically (and immigration reform more generally) is top of mind for tech leaders, many of whom are immigrants themselves.

Without immigrants, Silicon Valley would look a lot different than it does today.