Amazon will pay all its U.S. employees a minimum of $15 an hour, more than doubling the federal minimum wage. The online retailer, run by the world's richest man, was criticized earlier this year after revealing its workers' median pay was $28,446.

Amazon says the new rate will go into effect on Nov. 1, covering all of its full-time, part-time, temporary and seasonal employees in the U.S.

"We listened to our critics, thought hard about what we wanted to do, and decided we want to lead," said Amazon's founder and CEO Jeff Bezos, as the company announced the new pay scale Tuesday. "We're excited about this change and encourage our competitors and other large employers to join us."

At the new pay rate, an Amazon employee who makes the minimum would need to work more than 3 weeks (133 hours) to buy one share of the company, whose stock price currently sits just above $2,000.

The new minimum wage far exceeds the $7.25 federal minimum pay; Amazon says it will set the mark for more than 250,000 current employees, as well as more than 100,000 seasonal employees it plans to hire for the coming holiday season.

In addition to committing to higher minimum pay, Amazon says it will "work with policymakers in Washington, D.C., to advocate for a higher federal minimum wage."

The federally mandated minimum pay hasn't risen since 2009. And in that time, the $7.25 rate "has lost about 9.6 percent of its purchasing power to inflation," the Pew Research Center said last year.

From state to state, the minimum wage varies widely. In 29 states and Washington, D.C, it's higher than the federal rate. But in two (Georgia and Wyoming), it's lower, at $5.15. And five states have laws that don't require a minimum wage at all, according to the Department of Labor.

Amazon's new pay rate includes workers who are hired through temp agencies and subsidiaries in the U.S. The company also has more than 575,000 employees worldwide.

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