March 6 (Bloomberg) — Gary Cohen, the top health insurance regulator accused by congressional Republicans of misleading them before the troubled start of the Obamacare insurance website, will resign.

Cohen will step down as director of the Center for Consumer Information and Insurance Oversight at the end of the month, when the first enrollment period for the health-care law concludes, Marilyn Tavenner, the administrator of the Centers for Medicare and Medicaid Services and Cohen's boss, said yesterday in an e-mail to employees. Cohen's office is part of Tavenner's agency.

Cohen's departure is voluntary, Tavenner said. His agency devised the regulations for the Patient Protection and Affordable Care Act's insurance exchanges, though it wasn't responsible for building healthcare.gov, the federal exchange that failed in October, leaving millions of Americans unable to enroll in health plans. Cohen's office also monitors insurers' premiums and enforces consumer protections under the health law.