The regulation of health insurance in California is shifting dramatically toward the Department of Managed Health Care, whose share of the commercial market has mushroomed in recent years.

The California Legislature on Monday unveiled a bill imposing a new tax on health insurance plans that would prevent a massive $1.1 billion hole in the state budget.

More than 425,000 Californians have signed up on the state’s health insurance exchange — with nearly 100,000 rushing to enroll in the last four days before the 2016 open enrollment period ended Jan. 31, officials said Thursday.

Parker Conrad, CEO and co-founder of once high-flying Zenefits, has resigned amid a scandal involving allegations that employees sold insurance without holding proper licenses to do so.

Embattled drug entrepreneur Martin Shkreli — who vigorously defended his decision to hike the price of a life-saving drug from $13.50 to $750 — suddenly went silent Thursday at a Congressional committee, smirking and grinning instead of answering questions.

Stung by losses under the federal health law, major insurers are seeking to sharply limit how policies are sold to individuals in ways that consumer advocates say seem to discriminate against the sickest and could hold down future enrollment.