The paid leave arms race isn’t all it’s cracked up to be. While some employers—notably those in consulting and tech—have recently made splashy updates to their leave policies, the vast majority are staying quiet.

A new report from non-profit Paid Leave for the United States (PLUS) that aimed to parse the parental leave policies at the top 60 employers in the country found that 33 of them did not make the information publicly available. Of these, eight declined to share their policies with PLUS (the remaining 25 companies never responded to the non-profit’s requests to provide information): Boeing ba , FedEx fdx , Honeywell International hon , HPE, Infosys Limited infy , Marriott International mar , TJX tjx , and Walgreens wba .

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The companies didn’t offer an explanation for their reluctance to disclose their policies. However, Katie Bethell, founder and executive director of PLUS, says that some may be opting to keep their policies quiet because they don’t offer the same benefits to all of their workers. “One thing that seems to be problematic is discrimination against low-wage workers,” she says.

Walmart wmt , the largest employer in the country, was the only company to confirm that is excludes hourly workers from its paid leave benefits (salaried mothers get 12 weeks; fathers get two). However, Bethell believes that many other companies with large hourly workforces have similarly exclusionary policies.

It’s no accident that the companies that do have generous leave policies—Bank of America bac , Deloitte, and IBM ibm are among them—are those that compete for highly-skilled talent.

Hourly workers aren’t the only ones being left out. Of the 27 company policies PLUS was able to confirm, 22 have unequal leave, with fathers and/or adoptive parents receiving significantly less time than birth mothers. Seven companies offer no paternity leave at all: AT&T t , CVS cvs , General Motors @general m gm , Ford f , Starbucks sbux , Supervalu, and Verizon vz .

Offering leave to mothers but not fathers is not simply a corporate oversight. President-elect Donald Trump’s paid leave proposal also restricts paid leave to moms, something Bethell believes “has roots” in typical corporate policies.

“[Trump’s] program falls far short,” says Ellen Bravo, executive director of Family Values @ Work, a network of coalitions working for paid leave. “It would cover too few people—less than half. A low-wage worker simply wouldn’t be able to use it. We do not see that as the solution.”

Despite her disapproval of Trump’s proposal, Bravo believes that the responsibility to provide paid leave should not fall on the shoulders of corporations. “There are many businesses, particularly smaller business, who might want to make sure their employees are taken care of, but can’t compete,” she explains. Leaving paid leave up to the employer puts smaller companies at a major disadvantage, as they simply may not have the resources to provide it.

Bethell agrees that “ultimately, solving paid family leave will require a national public policy.” Currently, no such policy exists; the U.S. is the only OECD country without one.

The PLUS founder points out that the companies with operations in foreign countries—that is to say, most of them—comply with the laws in other countries that offer far more generous family leave. So an expecting father who is an employee in Finland, for example, would get 11 weeks of paid time off at 70% of his salary, while his American counterpart would get none.

“For most of these companies, providing paid leave isn’t much of a stretch,” says Bethell. “They’re already doing it—just not at home.”