Hedge-fund manager Edward Lampert has pumped an additional $1 billion into his yearslong effort to revive Sears, but the CEO’s latest financing likely is just another short-term fix for the struggling retailer.

On Wednesday, Sears Holdings Corp. said it obtained a $500 million loan secured by mortgages on 46 properties from affiliates of ESL Investments Inc., the hedge fund run by Mr. Lampert. That is in addition to a $300 million secured letter of credit that the retailer received from ESL affiliates last week.

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