Lending Club, one of the largest online lending services, said on Monday that its chairman and chief executive, Renaud Laplanche, had resigned after an internal review showed a violation of the company’s business practices.

The company said that the case involved sales of $22 million in near-prime loans to a single investor. The company said the sale was made in a way that was against the investor’s express instructions. The company did not say how the deal defied the investor’s wishes, but added that the issue did not have to do with credit quality or pricing.

Scott Sanborn, the company’s president, will be acting chief executive. One of its directors, Hans Morris, will become executive chairman.

“While the financial impact of this $22 million in loan sales was minor, a violation of the company’s business practices along with a lack of full disclosure during the review was unacceptable to the board,” Mr. Morris said in a statement. “Accordingly, the board took swift and decisive action, and authorized additional remedial steps to rectify these issues.”