An Indiana unit of Lake Success-based Newtek Business Services Corp. reopened Friday after being raided Thursday by FBI agents, company officials said.

FBI agents served a search warrant on banc-serv Partners LLC, based in Westfield, Indiana, and carried away documents from the company, which structures and packages Small Business Administration loans.

A spokeswoman for Newtek, which acquired banc-serv for $5.4 million in June 2016, said the company is cooperating with the investigation, but could not provide further details.

An FBI spokeswoman confirmed “investigative activity” at the company, but said she could not specify “the nature of that activity.”

A call to the U.S. Attorney’s Office for the Southern District of Indiana was not returned.

Newtek’s portfolio companies provide loans, credit-card processing, insurance, IT support and payroll services to small- and medium-size businesses.

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The company, with a market capitalization of about $293 million, posted sales of $31 million in 2016, a gain of more than 18 percent.

Shares of Newtek fell 4.4 percent to close Friday at $17.20. The stock has risen about 20 percent over the past 12 months.