However, hundreds of thousands of workers will not receive any payments. Here's a rundown of who should not expect the financial aid.
Perhaps the most significant barrier is a restriction that limits the subsidy to people who currently receive at least $100 a week in unemployment benefits from the state or another program.
The policy is a departure from the $600 enhancement, which was enacted by the CARES Act coronavirus relief law in March, which was available to any recipient of unemployment benefits.
Roughly 6% of workers collecting state unemployment insurance fall under the $100 threshold, and therefore don't qualify, according to an estimate from Eliza Forsythe, a labor economist and assistant professor at the University of Illinois.
That amounted to more than 912,000 people as of Aug. 1, according to Labor Department data.
The Trump administration imposed this rule to ensure people who lost side gigs, as opposed to a primary income source, can't collect the subsidy, John Pallasch, assistant secretary for employment and training at the U.S. Labor Department, said at a press conference last month.
However, the $100 threshold also leaves out many others, particularly those who earn lower wages and work part-time or seasonal hours — a group that would arguably benefit most from the unemployment assistance, according to some labor experts.
Others will fall through the cracks, too, due to quirks of the unemployment system and how benefit levels are determined, experts said.
The $100 restriction won't be a problem in some states, however.
Nine states — Arizona, Kansas, Michigan, Montana, New Jersey, New York, Ohio, Oregon and Washington state — pay a minimum benefit of more than $100 a week. That means all workers getting benefits in these states would qualify for Lost Wages Assistance.
Some states, like Idaho and Rhode Island, found ways to pay the extra $300 a week to ineligible workers anyway.
Self-employed, gig and other workers collecting benefits through the federal Pandemic Unemployment Assistance are also generally safe: All states pay a minimum PUA benefit exceeding $100 a week.
Alaska is the one state where there appears to be an exception, however.
The state will not issue Lost Wages Assistance to PUA recipients, according to Cathy Munoz, deputy commissioner of the Alaska Department of Labor and Workforce Development.
There are more than 12,000 people collecting benefits through that program, according to data from the U.S. Labor Department.
The issue is related to a cost-sharing requirement states must meet to receive the Lost Wages grants. Alaska wouldn't have been able to meet that requirement if it included PUA recipients in the mix, Munoz said.
Per a federal rule, workers can only receive the $300 weekly payments if they self-certify that they are unemployed or partially unemployed due to Covid-19.
Some labor advocates are concerned workers won't know to do this or will answer the question incorrectly, thereby disqualifying them from getting the subsidy.
Workers may think, for instance, that being unemployed "due to Covid-19" means they were out of work solely because they were infected with the virus.
Economic, as well as health, situations apply, said Andrew Stettner, an unemployment expert and senior fellow at the Century Foundation. Those may include losing a job because one's business closed or struggled during the pandemic, or losing a job due to childcare responsibilities, he said.
"My biggest concern is that people are going to say 'No' to that question when they should say 'Yes,'" Stettner said of the self-certification. "If you were laid off in January, you should probably say 'No,' but otherwise you should probably say 'Yes.'"
There's some evidence workers may not be aware of the self-certification requirement. For example, Louisiana, one of the first states to start disbursing the subsidy, e-mailed nearly 23,000 people that may qualify based on their unemployment circumstances a few weeks ago. Around 35% hadn't opened the e-mail as of Sept. 4, according to the Louisiana Workforce Commission.
PUA recipients previously self-certified as a condition of receiving their unemployment benefits, so likely won't need to take this step.
South Dakota is the one state that didn't apply for Lost Wages Assistance by the Sept. 10 deadline.
There were about 14,400 people collecting state unemployment insurance and 5,100 collecting Pandemic Unemployment Assistance in South Dakota as of Aug. 1, according to Labor Department data.