Shares rose around 50% to $3.81 after the reported negotiations, compared with a market value of roughly $389 million at the previous close.
IonQ plans to acquire Elisity for up to $1.3 billion in stock
The purchase would expand IonQ's quantum security business, with completion expected in the fourth quarter of 2026 pending regulatory approval.

Quantum computing company IonQ said on October 12 that it would acquire cybersecurity firm Elisity for as much as $1.3 billion, paid entirely in stock. The company expects the transaction to close in the fourth quarter of 2026, pending regulatory approval.
The maximum price includes performance-linked earn-outs of up to $150 million. The quantity of shares IonQ issues will be determined using a per-share price between $33.07 and $49.61.
IonQ said the purchase would broaden its channels for selling quantum offerings to enterprise and government customers. It said those offerings would help customers address existing security threats and prepare for potential attacks using future quantum computers.
Founded in 2019, Elisity has more than 100 customer deployments globally, according to IonQ. The company said Elisity's revenue and customer base had each doubled year-over-year. James Winebrenner, Elisity's CEO, will remain in charge of the business after completion.
IonQ also completed the purchase of chipmaker SkyWater Technology to internalize semiconductor manufacturing and advance work on its next-generation quantum processors.
