Two of the Carlyle Group’s three founders are selling a small portion of their shares in the company, the first time any insiders have liquidated holdings since the D.C.-based private-equity firm became a public company in 2012.

Co-chief executive William E. Conway Jr. and Chairman Daniel A. D’Aniello are each selling 1.215 million shares, worth about $42.8 million for each man, according to a filing Carlyle submitted to the Securities and Exchange Commission on Monday. The third co-founder, co-chief executive David M. Rubenstein, is not selling any shares, according to the filing.

Conway and D’Aniello will each continue to own about 14 percent of the company with more than 45 million shares apiece. Their remaining shares are worth more than $1 billion for each of them.

Longtime Carlyle managing partner and board member Edward J. Mathias is also selling $1.4 million worth of stock, and Carlyle general counsel Jeffrey W. Ferguson is selling approximately $1.6 million worth of shares.

The sales figures are based on Carlyle’s stock price of $36.27 at the close of business on Feb. 28.

Carlyle also plans to sell 12 million new common shares. Some of the proceeds will go toward “general corporate purposes, investments in our funds,” while the rest will help pay for the shares being sold by the company’s co-founders and others, according to the SEC filing.

A Carlyle spokesman declined to comment.

Carlyle stock has done well since its debut less than two years ago, climbing 60 percent from its initial public offering price of $22. It closed down 2 percent Monday at about $35 a share.

Conway and D’Aniello could not be reached for comment, and Carlyle’s SEC filing did not disclose what they would do with the profits from their stock sales. Forbes estimates that each of the three co-founders is worth $3.1 billion, thanks largely to their Carlyle holdings.

Conway, D’Aniello and Rubenstein took home about $750 million between them last year, mostly because of dividends paid by the private-equity firm and profits made off their personal investments in deals struck by Carlyle. The founders and other Carlyle employees committed to invest $1.1 billion of their personal capital with Carlyle in 2013.