Caesars Entertainment Corp. and Education Management Corp.have been stymied in their efforts to influence Congress to changea Depression-era law that's designed to protect lenders, accordingto people with knowledge of the matter.

The casino company owned by Apollo Global Management LLC and thefor-profit college backed by KKR & Co. tried last month toinsert an amendment into an early version of the landmark U.S.transportation bill that would have rolled back part of a 1939 lawknown as the Trust Indenture Act, said the people, who asked not beidentified discussing the actions because they haven't been madepublic. Without the changes, the companies may find it harder towin creditor lawsuits claiming actions they took to revise theirdebt violated parts of the act.

Caesars has said it will probably have to join its bankruptsubsidiary in Chapter 11 if it loses the suits, which are overactions the company took to shuffle debt before the unit filed forcourt protection. Apollo, which controls Caesars along with TPGCapital, could then lose its stake entirely in the casino giant.Education Management may have to pay out junior creditors whodidn't go along with its out-of-court debt reorganization, hurtingthe investment value of KKR, which is among the company's largestequity holders.