• The US government declined to share which small businesses have received loans under the Payroll Protection Program. 
  • Treasury Secretary Mnuchin told lawmakers that the information was considered proprietary and confidential. 
  • Usually, the Small Business Administration discloses loans it provides to companies. 

US taxpayers have shelled out more than half a trillion dollars in loans to businesses under the Paycheck Protection Program, but those same taxpayers haven't yet been able to find out which companies received the money.

Some 438 publicly traded companies have disclosed about $1.38 billion worth of loans in regulatory filings, according to FactSquared, which has been checking thousands of filings. In some cases, large companies returned the money (just under $1 billion worth) after public backlash forced the Treasury Department to tighten its rules for the program and more closely review applications.

But for the other $529 billion of loans that have been doled out, there is no current plan for public accountability. (Some $130 billion is still available.)

"We believe that that's proprietary information, and in many cases for sole proprietors and small businesses, it is confidential information," Treasury Secretary Steven Mnuchin told lawmakers on Capitol Hill on Wednesday. Usually, the Small Business Administration -- which has overseen the PPP -- discloses recipients of its loans.Axios notes that someone could theoretically deduce individual salaries from the loan disclosures, but a competitor would need to know how many employees that company has to even calculate average compensation, much less individual paychecks. What's more, PPP loans are based on past pay, which can obviously fluctuate, and don't include specifics above $100,000.

Some Democratic lawmakers disagree with this logic.

"How can we know which businesses still need help if we do not know which businesses have received help?" asked Sen. Ben Cardin of Maryland.

The move to shield loan recipients from public eyes comes after the government on Thursday lowered the percentage of payroll protection funds that must go toward payroll. Now, 60 percent of the amount eventually forgiven should go toward payroll, the SBA said, meaning that if a business was provided $20,000 through a loan, for example, and $6,000 went to cover payrolls, then it could be eligible for $10,000 in loan forgiveness.

Employment data released for the month of May could be a sign that the PPP was a success. That's something Mnuchin told lawmakers this week, and experts agree.

The unexpected and dramatic rise in employment "is clearly linked to the effectiveness of the PPP and other federally-funded re-payrolling initiatives," Dan Alpert, co-creator of the U.S. Private Sector Job Quality Index, told Business Insider.

--This post originally appeared on Business Insider