UnitedHealth Group Inc. reported second-quarter medical costs slightly higher than Wall Street expectations, sending the largest U.S. health insurer’s shares down 4 percent and weighing on the rest of the sector.

UnitedHealth Group Inc. posted first-quarter 2018 profit that beat estimates as the largest U.S. health insurer kept medical costs within expectations despite the added demand for services due to a strong flu season. UnitedHealth raised the group’s 2018 outlook.

The U.S. government said it would increase by 3.4 percent on average 2019 payments to the health insurers that manage Medicare Advantage insurance plans for seniors and the disabled, a higher-than-expected rise reflecting a projection of higher medical cost growth.

U.S. Food and Drug Administration chief Scott Gottlieb criticized pharmacy benefit managers, health insurers and drugmakers for “Kabuki drug-pricing constructs” that profit the industry at the expense of consumers.

Amazon.com Inc., Berkshire Hathaway and JPMorgan Chase & Co. will form a healthcare company aimed at cutting costs for their U.S. employees, they said on Tuesday, sending shares in the broad healthcare sector sharply lower.

The largest U.S. health insurer UnitedHealth Group Inc will buy DaVita Inc’s primary and urgent care services for $4.9 billion in its second acquisition this year.

CVS Health’s proposed purchase of Aetna will change the way many major U.S. corporations buy health coverage for employees, according to benefit consultants.

Ohio’s Department of Insurance said non-profit managed care company CareSource will sell health plans in Paulding County in 2018 – the last county in the United States that would have been without Obamacare individual coverage during the year.

Centene Corp., one of the largest players in the Obamacare individual insurance market, said it would offer Obamacare plans in Nevada in 2018.

U.S. health insurer Anthem Inc. said it will exit Obamacare markets in Virginia and reduce its plan offerings in Washington and Scott counties and the city of Bristol in 2018.