(CNN) The Trump administration is expanding employers' ability to give workers cash to buy heath care coverage elsewhere, including on the Obamacare exchanges, senior officials announced Monday.

The proposed regulation is aimed at broadening the use of health reimbursement arrangements, which are not very well-known. Employers use them to provide workers with tax-free funds to pay for health care costs, mainly deductibles and co-pays.

Prior to Obamacare, employers used Health Reimbursement Arrangements to reimburse workers for a wider array of expenses, including premiums. The Obama administration, however, barred the use of Health Reimbursement Arrangements to buy policies on the individual market.

The move is aimed at increasing health insurance coverage among those who work at smaller firms, many of which don't provide benefits. It would also allow employers who do offer benefits to give each worker up to $1,800 a year in an Health Reimbursement Arrangement to pay for certain health care expenses or buy dental or vision coverage.

Unlike most of the administration's other health care steps, this regulation could funnel more people into the Obamacare exchanges. Some 7 million more people could be insured through the individual market by the end of a decade, officials said. In total, an additional 10 million people at 800,000 employers could use Health Reimbursement Arrangements to buy coverage, including 1 million newly insured Americans.

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