Delta has hired prominent attorney David Boies to seek damages from CrowdStrike and Microsoft following an outage this month that caused millions of computers to crash, leading to thousands of flight cancellations.

CrowdStrike shares fell as much as 5% in extended trading on Monday after CNBC’s Phil Lebeau reported on Delta’s hiring of Boies, chairman of Boies Schiller Flexner. Microsoft was little changed.

On July 19, a software update from CrowdStrike led to a historic outage of Microsoft systems, knocking numerous industries offline. Airlines were particularly hard hit, and the Department of Transportation said last week that it’s investigating Delta, which suffered widespread flight disruptions and service failures.

CrowdStrike lost almost a quarter of its value in two trading days on concerns about the company’s business following the incident.

While no suit has been filed, Delta plans to seek compensation from Microsoft and CrowdStrike, Lebeau reported. Delta hasn’t responded to a request for comment.

The outages cost Delta an estimated $350 million to $500 million. Delta is dealing with over 176,000 refund or reimbursement requests after almost 7,000 flights were canceled.

Boies is known for representing the U.S. government in its landmark antitrust case against Microsoft and for helping win a decision that overturned California’s ban on gay marriage. He also worked with disgraced Hollywood mogul Harvey Weinstein and Theranos founder Elizabeth Holmes, who is currently serving a prison sentence for defrauding investors.

Insurance startup Parametrix estimated that the CrowdStrike incident resulted in a total loss of $5.4 billion for Fortune 500 companies, not including Microsoft.

WATCH: Potential Delta lawsuit not top of mind for Microsoft investors