In this Nov. 17, 2004 file photo, Kmart chairman Edward Lampert listens during a news conference to announce the merger of Kmart and Sears in New York. Gregory Bull | AP

Sears on Thursday lodged a lawsuit against its former CEO Eddie Lampert and a string of its high-profile past board members, including his former Yale roommate Treasury Secretary Steven Mnuchin, for allegedly stealing billions of dollars from the once-storied retailer. Sears Holdings filed for bankruptcy this past October, after years of losses under Lampert, who was then its chairman, CEO and largest shareholder. Lampert saved the retailer from complete liquidation by buying it through Transform Holdco, an affiliate of his hedge fund ESL Investments. But Sears' unsecured creditors repeatedly argued that Lampert was the cause of, not the solution to, Sears' downfall. They believe that Lampert, along with Sears' biggest shareholders, unduly benefited from deals that occurred under Lampert's watch, including its spinoff of Lands' End in 2014, and the carve out of many of its best properties into Seritage Growth Properties, a real estate investment trust Lampert created a year later.

Those claims laid the groundwork for the unsecured creditors to pursue their claims against Lampert and others on behalf of Sears. Lampert had requested a release from potential ligation as part of his deal to buy Sears out of bankruptcy but was denied the protection. "Altogether, Lampert caused more than $2 billion of assets to be transferred to himself and Sears' other shareholders and beyond the reach of Sears' creditors," the lawsuit alleged on Thursday. Among the allegations lobbed at Lampert, the company said he rejected a $1.6 billion offer for Lands' End from private equity firm Leonard Green & Partners and the Tommy Hilfiger investment group in favor of a spin that would keep his stake in the brand untouched. It cites an email from the company's then-CFO, Robert Schriesheim, who explained to another Sears employee that "[Lampert] was trying to optimize cash for [Sears] while maximizing his (esl) equity stake ... because he knows that [Lands' End] is worth a great deal outside of [Sears]." The filing claims Lands' End was distributed to Lampert, ESL and other Sears' shareholders for no consideration, following a prespin dividend of $500 million. On the stock's first day of trading, its value topped $1 billion, with Lampert's share worth at least $490 million. The stock currently has a market value of $591.3 million. It further alleges that Seritage's deal with Sears to give it ownership of 266 of Sears' best retail stores was not negotiated and undervalued the properties by at least $649 million. "The appraisals were fundamentally flawed and, among other things, intentionally used under-market future lease rates as the sole basis for their valuations," the suit alleged.