CrowdStrike first hoped to sell its shares for about $20. Demand pushed the price to $34, and the stock still closed its first day at $58. The company sold one product, Falcon, a small program that sat on every laptop and server and reported back to CrowdStrike's cloud. Old antivirus software looked for known bad files. Falcon watched for suspicious behavior. In June 2019, companies were tired of breaches, and investors wanted security that ran in the cloud.

One Sensor, One Cloud

George Kurtz and Dmitri Alperovitch founded CrowdStrike in 2011. Kurtz became chief executive and Alperovitch chief technology officer. Their bet was that a light sensor on each machine, joined to one big cloud, could spot attackers faster than antivirus on each computer working alone. Every attack seen on one customer's machine taught the system to protect the rest. Customers paid by subscription, and they could add new modules without new software.

Blue Screens Worldwide

CrowdStrike priced at $34 a share and began trading on the Nasdaq on June 12, 2019, under the ticker CRWD. The stock rose more than 70 percent that day. The company kept growing and moved its headquarters to Austin, Texas. On July 19, 2024, a faulty Falcon update crashed Windows computers around the world and grounded flights. CrowdStrike pulled the update within 80 minutes. The company is still public on the Nasdaq.

Cover: Hawk, from The Picture Book of Realistic Paintings of Hokusai, Katsushika Hokusai. Art Institute of Chicago, public domain. Chosen for a hawk on watch (the Falcon sensor).