Saban bought a 30% stake in Partner, Israel's second-largest mobile operator, from Scailex in 2013 using a $300 million loan from Hong Kong conglomerate Hutchison Whampoa.
Repayment is due in January 2020 and Saban had used his holdings in Partner as collateral for the loan.
In a filing with the U.S. securities regulator, Saban said his company, SB Israel Telecom, had been in discussions with debt owners regarding the loan's terms.
"At this time, it is unlikely that any agreement will be reached between SB and the lenders, and the lenders may exercise their rights," it said.
The value of Saban's holdings in Partner have slid to 733 million shekels ($209 million), less than the amount of the loan. Partner's market value stands at 2.4 billion shekels.
Partner's shares were up 0.2% in afternoon trade in Tel Aviv after a 2.7% drop on Sunday when Israeli media first reported Saban's intent to give up his holdings. Its shares are down 20% so far in 2019.
Hutchison founded Partner in the late 1990s and sold its stake to Scailex in 2009 before Scailex sold it to Saban.
Like its peers, Partner's revenue and profit have plunged in the wake of a 2012 reform that opened the mobile market to new players, sharply reducing prices. It is seeking new revenue streams such as a new TV service and pushing to widen its offering beyond its core mobile services.
(Reporting by Steven Scheer; Editing by Tova Cohen and Deepa Babington)