Simply put, the 2023 National Survey of Unbanked and Underbanked Households found that the number of American households without a bank account or credit union has reached an all-time low: 4.2 percent of U.S. households, or about 5.6 million homes. That’s the lowest that’s ever been documented by the FDIC, a reduction of almost half since the all-time-high back in 2011.

The reasons for this progress are multiple and complex. Lobbyists seeking to influence several regulations warn that if policy changes (or doesn’t change), many of those gains will be lost. But unpublished internal FDIC documents shared with Fortune show regulation is not among its key “areas of opportunity”—rather it’s technology that’s the big driver of progress.

“I don’t know that policy has really been a large part of this story,” says Keith Ernst, the associate director of the FDIC’s division of depositor and consumer protection, in conversation with Fortune during a break from the advisory committee meeting. “If you look over the last decade, what you’ve seen is innovation within industry.”

Specifically, Ernst credits one rather simple technological development as making the biggest difference: so-called safe accounts. Originally launched by the FDIC as a pilot with nine banks in 2011, safe accounts followed a publicly available model that leveraged banks’ more efficient back-end technology to offer low-income users easy access to interest-bearing accounts. The FDIC insured accounts had no overdraft or insufficient funds fees, and very low or no minimum deposit requirements. A year later 95% of the newly created accounts were still in use.

In 2015 the non-profit Cities for Financial Empowerment Fund launched the Bank On standard inspired by the FDIC pilot. The standard has been adopted by more than 470 banks and credit unions, including Chase, Wells Fargo, Bank of America and Citi. Last year savers at 47,000 branches and roughly 100 state and local coalitions deposited more than $174 billion into 11 million accounts, four million of which were new.

“These accounts have been taken up in large numbers across the population,” says Ernst. “[They’ve] proven popular with households that formerly were unbanked, but also with other households as well.”

Speaking to the potential influence of these accounts, the top reason for being unbanked given in the 94-page FDIC report is not having enough money to meet the minimum balance. The number three reason is that fees are too high. The second reason, which might not be solved with a new kind of account, is that people don’t trust banks.

Bank-banked Zelle could fill Venmo gap

Some herald cryptocurrency and buy-now-pay-later products technologies that help the unbanked, but the FDIC report found no evidence to support the claims. In fact, the only technology specifically mentioned as an area of opportunity in the unpublished FDIC documents are “P2P transfers within the banking system (e.g. Zelle).” Zelle is a product of Early Warning Services, owned by a consortium of U.S. banks.

Though the survey found that non-bank services like PayPal, Venmo, and Cash App were used by 51% of banked households, only 20% of unbanked households used the services. One theory for the disparity discussed by FDIC officials at a press meeting earlier in the week is that having a bank account is the most common way to get money to these services in the first place, a problem they say bank-owned Zelle might fix.

Though Ernst sees the steady rise in the number of banked Americans as a victory of the free market, a number of lobbying groups warn the progress could be undone by poorly thought-out controls.

The non-profit Consumer Bankers Association, which represents banking interests, says regulations that reduce fees everyone is subject to, like the CFPB’s proposed overdraft rule could make it financially unfeasible for banks to serve low-income neighborhoods. The non-profit National Community Reinvestment Coalition argues that an updated version of the Community Reinvestment Act requiring banks to serve low-income communities could also decrease banking access.

“The long term trend is that financial services are more and more important part of American lives,” says Ernst. “But these trends we’re seeing are not foregone conclusions.”