According to a Thursday 8-K filing with the Securities and Exchange Commission, the department store chain has borrowed $100 million from affiliates of Lampert's hedge fund, ESL Investments. ESL has also agreed to lend as much as $100 million more to Sears by Dec. 1.
To be sure, Sears can't secure a second round of $100 million from ESL until the retailer proves it has the necessary collateral to back it up, the filing said.
Any loans under the agreement announced Thursday are due in April 2018 and carry an 11 percent interest rate. For comparison, Sears' original loans under a January agreement carry an 8 percent interest rate and are due in July 2020, according to the filing.
The new loans are part of a $500 million credit facility backed by the mortgages on 61 of Sears' properties. Sears had initially borrowed the entire $500 million, but the company eventually repaid nearly $100 million by selling off some of its real estate, the filing said.
"We continue to focus on actions to provide the Company with additional financial flexibility to generate liquidity and demonstrate our ability to manage our business while meeting all of our financial obligations," a Sears spokesman told CNBC in a statement.
Much of Lampert's ESL portfolio today consists of retail companies, particularly Sears Holdings, which is also the fund's largest holding. Lampert founded ESL in 1988 with an initial outside investment of $28 million.
Meantime, Sears is working to return to profitability, and its efforts are particularly important heading into the holidays, when shoppers will be ringing up more purchases at malls across America.
In the second quarter, Sears' same-store sales tumbled 11.5 percent, as its revenue continued to erode. The department store chain also announced additional store closures in an effort to cut costs.