Blue Cross and Blue Shield of Minnesota and HealthPartners are joining the state's MNsure exchange in offering a special enrollment period so people who buy individual health plans can take advantage of new rebates offered by the state.

On Saturday, MNsure officials announced a special enrollment period that effectively extends from Jan. 31 to Feb. 8, the deadline for people to buy 2017 coverage through the government-run exchange.

Individual market consumers have the option of buying through MNsure or directly from health plans, so the moves announced Monday by the insurers will bring parity between the exchange and "off-exchange" markets.

The special enrollment periods (SEP) apply only to the state's individual market, where about 5 percent of state residents buy coverage. The market has been rocked this year by premium spikes that prompted lawmakers last week to provide 25 percent rebates to certain people who buy the coverage.

"The SEP will apply to our off-exchange products," said Catherine Scott, a spokeswoman for Bloomington-based HealthPartners, in a statement.

The Blue Cross HMO called "Blue Plus will mirror the MNsure special enrollment period," said Jim McManus, a spokesman with the Eagan-based insurer, in a statement.

The individual market primarily serves the self-employed and those who don't get coverage from employers or a government program.

The market has undergone significant changes since 2014, when the federal Affordable Care Act started blocking insurers from denying coverage to people with preexisting health problems. Some insurers have struggled to make the business profitable, with some boosting premiums and others withdrawing from the market as a result.

For 2017, it's not clear yet how many people are buying through MNsure as opposed to the off-exchange market. The MNsure market has reported record sign ups thus far, since more consumers likely are turning to the exchange for federal tax credits, but most people in previous years bought outside the exchange.

Last year, about 73 percent of the individual market enrollment bought in the off-exchange market, according to the state Commerce Department, so the moves announced Monday by carriers could impact a large number of people.

About 250,000 people last year bought individual market health plans. State officials estimated that about 125,000 people in the market would not obtain federal tax credits via MNsure, so they opted to extend the one-time rebates.

Eligibility for tax credits depends on income and household size — individuals with annual incomes below $47,520 qualify, compared with $97,200 or less for a family of four. Rebates are available to those who don't get a tax credit, including those who may qualify on income but don't because they bypass MNsure.

Twitter: @chrissnowbeck