Shawn O’Connor

Chief Executive Officer Simulations Plus

Last Reviewed: September 29, 2026

Executive Summary

Shawn O’Connor has been Chief Executive Officer of Simulations Plus since June 2018. The Nasdaq-listed company, based in Research Triangle Park, North Carolina, sells modeling, simulation and AI-based software and consulting that pharmaceutical companies use to discover, develop and commercialize drugs. In June 2026 he agreed to sell the company to the healthcare investment firm Altaris for $18.50 per share in cash, about $375 million in total, and shareholders approved the deal that August. Simulations Plus is his third turn as chief executive of a drug-development software company, after Pharsight and Entelos. Before those he spent years in finance and operating roles at technology companies.

Career Highlights

• Chief Executive Officer of Simulations Plus since June 2018; the company’s proxy names him its only principal executive officer for fiscal 2021 through 2025.
• Signed the June 2026 agreement for Altaris to acquire Simulations Plus for $18.50 per share in cash, about $375 million. Shareholders approved it on 27 August 2026, and closing is expected in the fourth quarter of 2026.
• Chief Executive Officer, President and director of Entelos Holding Corp., a quantitative systems pharmacology software and services provider, from 2011 to 2018.
• Chief Executive Officer, President and Chairman of Pharsight Corporation, a pharmaceutical decision-support software company, from 2002 to 2009.
• Earlier held finance and operating roles, including CFO and President and COO at QRS Corporation (1995-2000) and CFO at Diasonics (1988-1994).

Professional Journey

O’Connor began on the finance side of technology companies. From 1988 to 1994 he worked at Diasonics, Inc. in several positions that included Chief Financial Officer. He then spent 1995 to 2000 at QRS Corporation, rising from Chief Financial Officer to President and Chief Operating Officer.

In 2002 he moved into software for drug development, which has occupied the rest of his career. He was Chief Executive Officer, President and Chairman of Pharsight Corporation from 2002 to 2009. Pharsight made software and services to help pharmaceutical and biotechnology companies make better decisions in drug development and commercialization. From 2011 to 2018 he was Chief Executive Officer, President and a director of Entelos Holding Corp., which provided quantitative systems pharmacology software and services to the same market.

He joined Simulations Plus as Chief Executive Officer in June 2018. The company was co-founded by Dr. Walter Woltosz, who remains a director and major shareholder. It describes itself as a global leader in model-informed and AI-accelerated drug development. Its software includes GastroPlus, MonolixSuite, ADMET Predictor and DILIsym, and it pairs that software with consulting services for biopharma clients. O’Connor is an executive officer rather than a board member.

On 15 June 2026 Simulations Plus agreed to be acquired by affiliates of Altaris, a healthcare-focused investment firm, in an all-cash deal at $18.50 per share. The price was a 26% premium to the 60-day volume-weighted average and valued the transaction at about $375 million. “This transaction provides immediate and certain value to Simulations Plus stockholders, and we believe the transaction will better position us to serve our customers and accelerate innovation across product offerings,” O’Connor said when the deal was announced. The antitrust waiting period expired in August, and shareholders approved the merger at a special meeting on 27 August 2026. Closing still depends on the remaining conditions, including regulatory approvals in France. Altaris expects to combine Simulations Plus with Chemical Computing Group, a molecular design software company it already owns. Once the deal closes, Simulations Plus will be a private company and its stock will leave Nasdaq.

Education

University of California, Berkeley

Bachelor of Science, Business Administration