Exhibit 99.1 ICON Reports First Quarter 2025 Results First Quarter 2025 Results Gross business wins in the first quarter were $2,681 million and cancellations were$659 million. This resulted in net business wins of $2,022 million and a book to bill of 1.01. Revenue for the first quarter was$2,001.3 million. This represents a decrease of 4.3% on quarter one 2024 or a 3.2% decrease on a constant currency basis. GAAP net income was $154.2 million, resulting in$1.90 diluted earnings per share in quarter one ...