The abrupt dismissal of Molina Healthcare Inc.’s two top executives last week sent the company’s stock up by more than one-third last week.

The health insurance and health care provider largely caters to low-income patients on Medicare and Medicaid, and it expanded to provide insurance plans through the Affordable Care Act, a business model that could be turned on its head as a Republican repeal-and-replace effort moves forward in Congress.

Joseph White, named interim chief executive last week, said on a conference call with analysts that while the company stands by its guidance for this year, “looking beyond 2017, we continue to consider our options for (ACA) marketplace participation in 2018.

“I think everyone is well aware of the variables in play here, funding of the cost sharing … and enforcement of the individual mandate … all create uncertainty around the future of the marketplace,” White said.

The ouster of Dr. J. Mario Molina as chief executive, a post he had held since 1996, and John Molina as chief financial officer spurred speculation among some analysts that the company could be for sale, perhaps another factor contributing to the surge in its stock price.

The board cited poor financial performance in its move to replace the Molinas, who retain their seats as directors.

While Long Beach-based Molina Healthcare, started by Dr. C. David Molina in 1980 as a clinic for low-income patients, saw its membership and revenue grow last year, income fell short, according to the company’s annual financial report.

Revenue in 2016 grew to $17.8 billion from $13.2 billion in 2015, as membership climbed to 4.2 million from 3.5 million, the report said. However, net income fell to $52 million last year from $143 million in 2015.

The company’s Ebitda dropped to $467 million last year from $508 million in 2015. Molina had issued revenue guidance of $720 million for 2016. Diluted net income per share fell to 92 cents in 2016 from $2.58 a year earlier, despite guidance of $3.50.

Molina also released its first-quarter 2017 results last week, reporting net income rose to $77 million from $24 million in the first quarter of 2016, and net income per diluted share increased to $1.37 compared with 43 cents for the same period last year.

Shares of the company rose $15.58, or 32.1 percent, for the week ended May 3 to close at $64.15, up 21.5 percent from a week earlier and 20 percent above its share price a year ago.