Fixed income and long-only investors in beleaguered Teva Pharmaceutical Industries Ltd. (TEVA - Get Report) are predicting the generic drug maker's investment grade debt rating could soon be slashed to junk, Evercore ISI analyst Umer Raffat wrote to clients.

Raffat cited feedback from investors, who think Teva's growing debt load makes it "highly likely" the Israeli firm will soon face a credit rating debacle despite a $5 billion debt paydown planned for this year. Teva could have to renegotiate some debt agreements with lenders next year unless it can trim at least $900 million from its debt load, Raffat said.

On Wednesday, Mylan NV (MYL - Get Report) received FDA approval for the generic variety of Copaxone, Teva's top-selling multiple sclerosis drug. Moody's said in a Wednesday release that the Copaxone development is a credit-negative event for Teva, which it rates as Baa3 negative, but didn't change its rating or outlook for the firm.

Teva stock traded down 1.03% to $15.91 midday Thursday. Since the start of the year, shares have shed 56.1% of their value.

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