The Centers for Medicare and Medicaid Services said Monday that it is proposing a 0.09% net average year-on-year payment increase next year.

The Wall Street Journal reported that the proposed increase is well below Wall Street expectations.

UnitedHealth (UNH) shares sank 20% as intraday trading volume surged to over 50.7 million from a daily average of roughly 7.53 million.

Humana (HUM) shares dropped 19%, with intraday trading volume rising to more than 7.31 million from a daily average of about 1.41 million.

CVS Health (CVS) shares shed 14% amid an increase in intraday trading volume to over 31.9 million compared with a daily average of almost 7.46 million.

Centene (CNC) shares slumped 10% as intraday trading volume climbed to over 8.49 million versus a daily average of about 7.6 million.

Price: 281.96, Change: -69.68, Percent Change: -19.82