U.S. stocks closed lower, extending a slump that left Wall Street with its worst week since April. The S&P 500 fell 0.7% Friday, its third straight drop since setting a record high on Tuesday. The Dow Jones Industrial Average sank 0.9%, and the Nasdaq composite lost 0.8%.

The losses came as businesses around the world scrambled to contain the effects of a disruptive technology outage. Cybersecurity firm CrowdStrike sank after saying the issue believed to be behind the global outage affecting flights, banks and medical offices lay in a faulty update sent to computers running Microsoft Windows. Treasury yields ticked higher.

Appeals court allows EPA rule on coal-fired power plants to remain in place amid legal challenges

In a victory for President Joe Biden’s administration, a federal appeals court on Friday ruled that a new federal regulation aimed at limiting planet-warming pollution from coal-fired power plants can remain in force as legal challenges continue.

Industry groups and some Republican-led states had asked the court to block the Environmental Protection Agency rule on an emergency basis, saying it was unattainable and threatened reliability of the nation’s power grid.

The EPA rule, announced in April, would force many coal-fired power plants to capture 90% of their carbon emissions or shut down within eight years. The rules are a key part of the Democratic president’s pledge to eliminate carbon pollution from the electricity sector by 2035 and economy-wide by 2050.