Career Education Corp. reported that it received a formal order of investigation from the Midwest Regional Office of the Securities and Exchange Commission .

The company, which operates 80 colleges and universities in the United States and overseas, said it intends to continue to fully cooperate with the probe. Career Education first announced the SEC’s investigation in March. Career Education was initially contacted by the SEC about an informal investigation on Jan. 7, according to Reuters.

Previously published articles reportedly detailed charges by former employees that involved the falsification of student records at two schools. “We believe that the inquiry was prompted by news reports concerning our Gibbs College/Montclair and Brooks Institute of Photography schools,” the company said in its government filing in March, according to Reuters.

The company is also being sued by shareholders who claim that Career Education falsified student records and financial statements at unspecified schools to inflate its stock price, according to Reuters.

Shares of Career Education Corp. plunged about 21 percent on Wednesday.