More than 100 publicly traded companies have taken advantage of the Small Business Administration's Paycheck Protection Program, the federal COVID-19 relief loan package designed to help small businesses retain employees.

While public companies are allowed to tap the program, reports of multimillion-dollar loans to large businesses have raised the ire of both the public and government officials. Sen. Marco Rubio, R-Fla., said his congressional committee would use subpoena power to conduct "aggressive oversight" of borrowers' certifications. On April 23, the Treasury Department updated a guidance document to suggest that big public companies are unlikely to qualify for the loans.

An S&P Global Market Intelligence analysis found 134 publicly traded companies have disclosed PPP loans totaling $550.6 million, including a $20 million loan for Ruth's Hospitality Group Inc. and $10 million loan for Shake Shack Inc. that both companies pledged to return. Ashford Hospitality Trust Inc. subsidiaries racked up the largest PPP loan at $30.1 million, followed by Meritage Hospitality Group Inc. with $29.1 million.

Among lenders, JPMorgan Chase & Co. processed the most loans for public companies, at $145.9 million, followed by KeyCorp processing $77.5 million.

At issue is a certification that the borrowers need PPP loans, which are guaranteed by the Small Business Administration, to support ongoing operations and prevent layoffs. That differs from the longstanding SBA 7(a) program, which requires that borrowers state they are unable to access credit elsewhere. The coronavirus relief legislation specifically struck that certification for PPP loans, said Rick Giovannelli, a partner for law firm K&L Gates who represents businesses on M&A and financing.

"Many companies reasonably read that to mean: But for getting this loan, I'd be laying people off," he said in an interview. "What [Treasury Secretary Steven Mnuchin] seems to be saying is that it's not enough to say that you're going to lay people off but for this loan. It's that you needed the money, that it was necessary on some higher level. That very well may approach the 'no credit elsewhere' standard."

Giovannelli said his conversations with borrowers have changed over the last few days following the statements from Mnuchin and Rubio. He said borrowers previously believed that if they applied for loans in good faith, they would be in compliance. Now, they are less sure.

"We absolutely are now seeing borrowers who are having to make a very hard decision about whether to take the loan proceeds or make a more significant reduction in their payroll," he said.

Scrutiny has intensified because the initial $349 billion allocation for PPP lasted less than two weeks. While Congress has passed a new bill adding another $310 billion and President Donald Trump is set to sign it, bankers think those funds will not last long. Some small-business owners report they were unable to access the program, raising the level of frustration.

"I'm annoyed as a business owner that I'm competing with them because they're not eligible for regular SBA loans, so why should they be eligible for this program?" said Matt Watson, founder of Country Club Prep, a clothing retailer with one location in Georgia and another in Virginia, as well as an online presence. "At the same time, it's Paycheck Protection and the person working for them shouldn't suffer. As long as it's used for payroll, do we care about that distinction?"

Watson said he received roughly 60% of his PPP request before the money ran out.

Shake Shack attracted significant media attention for its $10 million PPP loan, in part because the publicly traded company announced a $150 million equity raise at nearly the same time. On April 20, the restaurant chain said it would return the PPP loan.

"The optics are bad on that," Giovannelli said, adding that companies typically lay off employees as revenue declines. "They're not going to wait to cut expenses until they've burnt down to their last dollar."

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Large banks have been the top lenders to publicly traded companies. JPMorgan published a question-and-answer document that stated the company did not prioritize large clients. However, the document noted that small businesses applied through its business banking segment, which did not finish processing a crush of applications, whereas larger corporations applied through a commercial bank division that completed most of its applications.

Smaller lenders say they are taking advantage of the big banks' inability to serve their smaller customers. Wintrust Financial Corp. executives described a "halo effect" that should translate to new, long-term clients. Thomas Capasse, chairman and CEO of nonbank lender Ready Capital Corp., said his company has seen intense demand from customers unable to access PPP through their existing bank. Ready Capital reported it has processed $3 billion of PPP loans.

"When thinking about the efficacy of the program and the public policy of actually benefiting truly small businesses, those companies that are under 50 employees and who borrow under $350,000, that is the meat and potatoes of who this program should be benefiting," Capasse said in an interview.

Click here for a complete list of publicly traded companies to disclose PPP loans.