The Department of Labor on Wednesday will finalize a rule extending overtime protections to 4.2 million more Americans currently not eligible under federal law, boosting wages by $12 billion over the next 10 years, the White House said Tuesday evening.

The updated rule, which takes effect Dec. 1 and doubles the salary threshold below which workers automatically qualify for time-and-a-half wages to $47,476 from $23,660 a year, or from $455 to $913 a week. Hourly workers are generally guaranteed overtime pay regardless of what they make.

"We're strengthening our overtime pay rules to make sure millions of Americans' hard work is rewarded," President Obama said in a statement. "If you work more than 40 hours a week, you should get paid for it or get extra time off to spend with your family and loved ones."

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One of those Americans, Obama said, is Elizabeth Paredes, a single mom from Tucson, Arizona, who works as an assistant manager at a sandwich shop. "Elizabeth sometimes worked as many as 70 hours a week,without a dime of overtime pay," Obama said. "So Elizabeth wrote to me to say how hard it is to build a bright future for her son. And she's not alone."

Overtime protections have eroded over the past 40 years, with the share of full-time workers that qualify for overtime based on their salaries dropping to 7 percent from 62 percent in 1975, Obama said. "This policy just hasn't kept up with the times."

The long-awaited regulation has been many months in the making. Obama nearly a year ago announced the rule change, which will be automatically updated every three years.

The president also pitched his plan in an editorial published last June by Huffington Post, asking: "Will we accept an economy where only a few of us do exceptionally well? Or will we push for an economy where every American who works hard can contribute to and benefit from our success?"

Conservatives and business groups including the U.S. Chamber of Commerce have voiced opposition to Obama's plan, saying it would discourage companies from creating jobs and hinder economic growth.

Sen. Lamar Alexander of Tennessee, a Republican who chairs the Senate's labor panel, blasted the idea as intended "to make it as unappealing as possible" for companies to create jobs.