Workers are calling the shots in an ever-tightening labor market. So why should they wait a week or two before they see their paychecks?

A small but growing number of U.S. workers can draw from their earnings daily instead of on a more traditional weekly, biweekly or monthly basis under a new service offered by a startup called Instant Financial.

The service lets the employees tap half the pay they earn on a given day as soon as their shifts end. The offering is chiefly being targeted to hourly workers, many of whom live paycheck to paycheck and sometimes seek small advances such as payday loans to get by.

“It’s putting everybody in control of their pay,” says Steven Barha, CEO of Instant Financial. “It’s having a little bit of money when you need it.”

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Here’s how it works: Workers are notified, typically on their smartphones, at the end of their shifts that they have an hour to tap half their pay and are asked if they wish to do so. The money is instantly downloaded onto their debit cards. No taxes are deducted until employees receive their paychecks. And there’s no fee for workers, though businesses pay Instant Financial $1 per active user each month.

Limiting the money available to 50% of their paychecks encourages saving. And the one-hour window to draw the money discourages impulse purchases later in the day.

About 150,000 employees of 50 companies have access to the service, which was rolled out early this year. Most of the firms are restaurant and hotel companies with lots of hourly workers, including franchisees of McDonald’s, Outback Steakhouse and Dunkin’ Donuts, as well as some retailers, trucking companies and staffing firms, Barha says.

But he adds that company executives expect about 1 million workers to gain access in two years. About 78 million Americans, or 59% of the U.S. workforce, are hourly employees and could serve as a prime target market, says Ron Hanscome, a research vice president for Gartner.

Seventy-eight percent of workers are living paycheck to paycheck to make ends meet, according to a CareerBuilder survey conducted in the spring.

Within five years, Hanscome expects the service to be offered by major payroll providers and adopted by a large portion of the restaurant, hotel and retail industries, which employ about 32 million people, or 26% of the U.S. workforce. He knows of no other payroll firm currently offering the service, though he says a few companies, including ride-hailing firms Uber and Lyft, provide similar proprietary services to at least some employees.

Payroll processor ADP says it already offers the service but would not disclose how many businesses and employees are using it.

The offering is employers’ latest response to a 16-year-low unemployment rate of 4.2% and a hyper-competitive labor market in which businesses are struggling to find qualified workers. Job openings hovered near a record 6.1 million over the summer, with 1.5 million in retail and leisure and hospitality, which includes restaurants and hotels.

“If I’m getting paid $15 an hour and I get offered $15.50 but the other company doesn’t offer the service, I might stay,” Hanscome says.

Ed Shaw, executive vice President of Caspers Company, which owns 53 McDonald’s franchises in the Tampa, Fla., area, says its employee turnover rate edged up last year and the company received far fewer job applications as more employers competed for a smaller pool of workers. But since it adopted the instant pay service, its turnover rate has fallen by 10 percentage points, he says.

“This is helping our people a lot,” he says. “There’s a loyalty to the company because they appreciate the fact that we’re thinking of them.”

He says about 1,000 of Caspers' 3,350 workers have access to the service, and about one in five of those download money at least occasionally.

Malexus Graham, 20, a manager who earns $11.75 an hour at a McDonald’s in Tampa, says she uses it every day.

“You can use it to get something to eat, or get gas or pay a bill,” Graham says. “I don’t have to wait for it – it’s right there on my card.” Before, she says she sometimes deferred small purchases, such as groceries or personal care items, until her next paycheck.

This week, she says, she drew cash to buy medicine for her two-year-old son who had a fever. “It’s a big help.”