Companies across the country are trying to convince a federal judge that a new change to the U.S. immigration system would hurt innovation and the economy. Leading the effort is Seattle startup Boundless, whose CEO is an example of the type of entrepreneur who might be barred from the U.S. under the new rule.

The so-called “public charge” rule establishes more rigorous criteria for immigration officials deciding whether to grant legal status to immigrants. Boundless CEO Xiao Wang immigrated from Nanjing, China as a child. He told GeekWire, “this rule absolutely would have put my family’s journey to the U.S. at risk.”

But Wang’s campaign against the rule isn’t just personal. His company builds software and resources to help foreign-born customers navigate the U.S. immigration system. Boundless has advocated against several of President Donald Trump’s policies designed to curb legal immigration.

Today, more than 100 U.S. companies signed onto a friend-of-the-court brief organized by Boundless, outlining the potential harms the public charge rule could cause. Microsoft, Reddit, Redfin, and Twitter are among the signatories.

The letter was filed with the U.S. Court of Appeals for the Fourth Circuit, which is considering the case. In October, three federal judges blocked the Trump administration from implementing the policy.

The public charge rule empowers the government to deny applications from immigrants who use public benefits, like Medicaid. It also raises the minimum income required to be eligible for a green card. There are other factors that the policy allows immigration officials to consider, such as age and health.

The goal is to reduce the number of immigrants who rely on government assistance, and therefore taxpayer dollars, according to the Trump administration.

“It’s a level of subjectivity that has never been applied before,” Wang said.

In addition to organizing the amicus brief, Boundless launched a “Public Charge Estimator” to help immigrants determine how the new rule could affect them.

“It will reduce the talent pool available to employers,” Wang said of the rule. “When we look at the data, based off our estimator, it could prevent half of spouses of U.S. citizens and permanent residents from getting their marriage green card and getting their employment authorization.”

A federal judge for the Second Circuit Court of Appeals upheld the injunction on the rule implemented by lower courts. The Trump administration has asked the Supreme Court to review the matter.