Martin Shkreli loves to talk.

Whether on Twitter, in online streaming videos or in interviews with the news media, Mr. Shkreli, a New York businessman, has shown little reserve when it comes to discussing the pending federal securities fraud charges against him, or his rationale for increasing the price of a decades-old drug by more than 5,000 percent at a pharmaceutical company he ran until last month.

On Tuesday, Mr. Shkreli, 32, will get his chance to talk some more. A congressional committee has served a subpoena on him and ordered him to appear for a hearing to discuss pricing trends and other developments in the drug industry, according to documents reviewed by The New York Times.

The subpoena directing Mr. Shkreli to appear before the House Committee on Oversight and Government Reform was served by email to one of his lawyers at Arnold & Porter on Jan. 11.

But whether or not Mr. Shkreli will appear on Tuesday, let alone testify, is an open question.

Wednesday afternoon, Senator Susan Collins, the chairwoman of the Senate Special Committee on Aging, took to the floor of the Senate, to provide an update on that committee’s own investigation into large increases in drug prices. Ms. Collins, a Maine Republican, said Mr. Shkreli had refused to comply with a committee subpoena sent on Dec. 24 seeking documents by asserting his Fifth Amendment right against self-incrimination.