Quadrangle Group, the struggling private-equity firm co-founded by former car czar Steve Rattner, has embarked on a round of layoffs as it attempts to overhaul its business.

Sources familiar with the firm’s plans said some employees have been handed pink slips over the past few days as the firm goes through a yearend review process. It’s unclear how many of the investment shop’s staff of around 35 employees will be axed.

Co-President Michael Huber declined to comment.

The layoffs come as the investment firm, which once boasted 90 employees and managed $6 billion at its peak, winds down its existing business and attempts to re-invent itself under a new name that has yet to be revealed.

Quadrangle is expected to announce one or two high-level executives to help manage its existing portfolio of assets, possibly as early as next week, one source said.

As The Post first reported, other top executives are either leaving or scaling back their involvement, including Joshua Steiner, who is expected to take on a lesser role at the firm, and managing principal Andrew Frey, who will leave by the end of the year.

Launched nearly a decade ago, Quadrangle has struggled since Rattner left the organization in February 2009 to help President Obama oversee the bailout of the cratering car industry.

Both Rattner and Quadrangle have been caught up in the pay-to-play-scandal involving the state pension fund. Quadrangle settled investigations by the Securities and Exchange Commission and Attorney General Andrew Cuomo in April.

Rattner, who wasn’t part of the Quadrangle settlement, paid $6.2 million to the SEC and accepted a two-year ban. But Cuomo’s office is still pursuing its case against Rattner and is seeking $26 million in penalties and a lifetime ban. mark.decambre@nypost.com