Investors pounded four Orange County-based public company stocks in Monday trading over planned Medicare cuts for nursing homes and concerns that more are coming.

Sun Healthcare Group Inc. of Irvine lost more than half its value—its shares closed down 52% on Monday. Foothill Ranch-based Skilled Healthcare Group Inc.’s shares fell nearly 43%, while Mission Viejo’s Ensign Group Inc. closed down 22%.

Sabra Health Care REIT Inc., an Irvine owner of nursing homes, saw its shares fall more than 23% Monday.

Government officials late last week said they were cutting Medicare payments to nursing homes by more than 11% for the 12 months starting Oct. 1. In addition, there are concerns that large spending cuts required to pass a law to raise the federal debt ceiling would come from Medicare.