The mercurial life of Northern Oil & Gas has been turbulent, even for the volatile energy trade.

Northern is marked by early-stage stock killings by insiders and executives, dubious short sellers who long doubted the story, and disappointed investors since 2011 as its stock fell from a high of nearly $32 per share to $5, amid the 2015-16 bust in the fields of North Dakota and Montana.

Last week, Northern said CEO Michael Reger was fired after a disclosure by the Securities and Exchange Commission (SEC) that it had made a preliminary determination to pursue an enforcement action against him. The disclosure was in connection with an SEC investigation into possible stock manipulation involving Dakota Plains Holdings, a faltering company in which Reger was an initial investor. Both are based in Wayzata.

Reger, who made more than $10 million in compensation at Northern over several years, sued the board. He charged he was terminated unfairly, defamed and deprived of a severance package.

In the past, critics have raised questions about interlocking relationships and conflicting allegiances among owners and executives at Northern, Dakota Plains and Emerald Oil, a now-bankrupt Denver oil company started by Reger’s brother. The firms, including Dakota Plains, were started several years ago as public companies by acquiring low-cost, nonoperating public companies known as “shells,” rather than the traditional path through initial public offerings of stock.

Reger, and former Northern President Ryan Gilbertson helped finance Dakota Plains in the investment deal under SEC investigation for stock manipulation. Reger and Gilbertson have denied wrongdoing and said they were cooperating with the SEC investigation.

The Star Tribune in April reported that documents revealed that Reger and Gilbertson participated in a $9 million financing package that helped launch Dakota Plains in 2012. The promissory notes, or loans, had an escalator clause that paid note holders a bonus based on Dakota Plains’ stock price in the first 20 days of trading.

The stock price rose quickly to $12 and stayed near that price for almost exactly 20 days.

Northern, started in 2007, invests in oil leases and drilling projects in North Dakota’s oil fields. Dakota Plains is publicly traded oil-and-sand transport firm.

Northern shares have been sliding since 2011 when its stock peaked. It was battered by detractors known as “short sellers”who bet against its accounting and the value of its land holdings. Reger and Gilbertson had sold about $20 million worth of stock in the spring of 2011 at $18 to $32 per share.

Reger and his board replaced Northern’s auditor, chief financial officer and general counsel under shareholder pressure.

Reger hails from a Montana land-brokerage family business. He earned business degrees from the University of St. Thomas. Gilbertson was a securities trader for Piper Jaffray before joining Reger at Northern Oil.

Reger’s brother, James, started Denver-based Voyager Oil by taking over a shell company controlled by Lyle Berman, the Twin Cities gambling executive, who was Voyager’s first chairman in 2010. The Reger family made millions when since-bankrupt Voyager, now named Emerald Oil, went public several years ago.

A shareholder brought suit in 2012 against Reger and Gilbertson, another former Northern executive, Wayzata financiers Joe Geraci and Doug Polinsky and other insiders arguing that they had formed Voyager as a competitor to Northern to enrich themselves, arguing that they violated their fiduciary obligation to Northern shareholders. The case was dismissed by a federal judge in St. Paul who said there was no evidence of wrongdoing.

Meanwhile, Northern Oil has hired an investment banker, often a precursor to a sale or other strategic moves. 

Neal St. Anthony has been a Star Tribune business columnist and reporter since 1984. He can be contacted at nstanthony@startribune.com.