Citadel Advisors and Millennium Management sharply increased their Fabrinet positions in the second quarter, according to Form 13F disclosures, adding to signs that large investors were building exposure before the optical manufacturing specialist posted record results and pointed to sustained AI infrastructure demand. Citadel raised its holding from 4,963 shares to 151,705 shares, while Millennium increased its position from 61,692 shares to 164,313 shares. Fabrinet later told investors its customer base had become more diversified, with Cisco Systems, Inc., Nvidia Corp, Nokia Corp and Amazon.com Inc. each contributing 10% or more of total revenue in 2026, and said data center applications accounted for 51% of fiscal 2026 revenue. Management struck a notably confident tone on demand, with Chief Executive Officer Seamus Grady saying there was "no end in sight" to customer demand. The filings do not show why the funds bought the stock and only reflect holdings as of June 30, 2026, but they coincided with one of Fabrinet's strongest operating periods and reinforced the company's growing role in AI infrastructure.