This story is developing. Please check back for further LendingClub updates.
Subpoenas are the first step in an investigation. LendingClub shares briefly pared gains but rebounded, up nearly 7 percent after the news, after having fallen more than 77 percent over the past year.
A Lending Club spokesman told CNBC it "intends to fully cooperate with the New York State Department of Financial Services."
The probe is unrelated to the recent ousting of CEO Renaud Laplanche, sources told the The Wall Street Journal, who initially reported the story.
Laplanche had resigned as chairman and CEO as an internal review discovered staff knowingly sold $22 million in loans in March and April 2016 that did not meet the buyer's requirements. The investigation also led to the firing or resignation of three senior managers.
LendingClub offers a technology platform that aims to make credit more affordable than traditional lending platforms.
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— CNBC's Jim Forkin, Fred Imbert and Jon Marino contributed to this report.