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Big banks face competition from startup challengers on fees, apps and direct deposits. During the Covid era, that battle is expanding to which company can pay out stimulus checks the fastest.

Big-bank customers complained over the weekend about how their $1,400 stimulus payments were still pending in their bank accounts. Those payments may not arrive until Wednesday, nearly a week after President Joe Biden signed the historic $1.9 trillion economic relief package into law.

Newbies in the banking space are moving much faster. By Monday afternoon, Chime, the most valuable US consumer fintech startup, had already made about $3.5 billion in stimulus payments to more than a million customers, the startup told CNN Business.

Digital bank Current says it immediately credited member accounts, with the funds beginning to flow at 11 am ET on Friday.

The difference in timing can be significant to many customers, especially those whose careers have been sidelined by the pandemic. And it’s a way for fintechs to stand out from their better-known and much larger rivals.

“Affluent people may ask: What’s the big deal? Well, it means a lot if you’re living paycheck to paycheck, trying to make ends meet,” Chime co-founder and CEO Chris Britt told CNN Business on Monday. “Who doesn’t want to get paid sooner? It gives you flexibility to take care of your financial needs and live life, especially when people are struggling.”

How Chime pays early

All of this raises the question: Why are Chime customers getting their checks from Washington before Chase customers?

Large payments like paychecks and stimulus money flows through the banking world through the ACH system, which is run by the Federal Reserve. When transactions are initiated, banks receive a notification indicating money is on the way, effective a given date.

Unlike traditional banks, Chime doesn’t wait for the money to actually arrive. It pays it out early, not just for stimulus checks but paychecks and tax refunds as well.

“I guess you could argue we’re taking a risk,” Britt said. “But we’ve been told by the Federal Reserve that the money is coming so we don’t think it’s that much of a risk. It’s a choice the big banks could make. They certainly have the balance sheets to do it.”

Chime pays out early even when it’s not Uncle Sam cutting the checks. The startup estimates it gives customers early access (typically two days early) to more than $3 billion of payroll direct deposits each month.

Chime is valued at $14.5 billion, making it the most valuable consumer fintech in the United States, according to PitchBook. But Chime isn’t actually a bank. It’s a fintech platform that partners with FDIC-insured lenders Stride Bank and The Bancorp Bank to offer checking and savings accounts.

As a private company, Chime doesn’t release its number of customers. But the startup says it’s opening hundreds of thousands of bank accounts each month. And at least some of those customers are coming from big banks.

‘Off the charts’ buzz from customers

Over the weekend, Chase and Wells Fargo (WFC) responded to customer complaints about the whereabouts of their stimulus payments.

Wells Fargo noted that it will “process all of the direct deposits according to the effective date provided by the US Treasury.”

The payments are expected to reach about 90% of US families, according to the Penn Wharton Budget Model.

Sarah Grano, a spokesperson for the American Bankers Association, told CNN Business that US banks have delivered more than 300 million stimulus payments “safely and effectively” over the past year. “They are doing the same with this third round, and will deliver them as requested by the government on March 17, the day Treasury will actually transfer funds for credit to individual accounts.”

The day after Biden signed the American Rescue Plan into law, Chime tweeted out a “stimmy alert” indicating it had already made $600 million available to about 250,000 members.

“Once we sent out our stimmy alert, the amount of love we got from customers was off the charts once we sent,” Britt said.

Chime made a similar splash last spring when it gave members early access to $1.5 billion in stimulus payments. The startup said that set off its biggest enrollment day ever.

But Britt insists the accelerated payments are hardly a PR stunt.

“We didn’t do early stimulus payments as a marketing plan. That wasn’t the calculus,” Britt said. “It’s about our mission to be member-obsessed, be human and helping our customers when they’re in a jam.”

CNN Business’ Alexis Benveniste contributed to this report.