A Delaware County man previously convicted of securities fraud pleaded guilty Wednesday to a scheme to artificially inflate stock prices to make at least $3 million.

Howard M. Appel, 57, of Wayne, was ordered detained by U.S. District Judge Paul S. Diamond in Philadelphia after pleading guilty to one count of conspiracy to commit securities fraud.

"This habitual fraudster manipulated the markets to further his own self-interest," U.S. Attorney William M. McSwain said in a statement.

From 2008 to 2010, Appel was incarcerated in federal prison after pleading guilty in New York to conspiracy to commit securities fraud, and then was under supervised release until June 8, 2013, according to a Securities and Exchange Commission civil complaint filed in connection with the criminal case.

In the current cases, Appel orchestrated his fraud from 2012 through 2013, the SEC complaint says. The companies involved were Virtual Piggy Inc., Red Mountain Resources Inc., and Rio Bravo Oil Inc. Appel has agreed to settle the SEC charges and will be barred from serving as an officer or director of a public company.

In the criminal case, Appel is scheduled to be sentenced Nov. 26 and faces a maximum five years in prison. He also faces a financial penalty that could equal twice the amount of his monetary gain.