Riley O'Brien

RILEY O’BRIEN advises startups, founders, venture capital funds, and strategic investors navigating growth, risk, and opportunity. Riley counsels clients across the full lifecycle of private companies, from formation and ongoing governance matters to complex financings, exits, and other strategic transactions. Having practiced in Canada and Bermuda, he brings a cross-border perspective to complex transactions, with experience spanning biotech, life sciences, software/SaaS, fintech, digital health, AI, consumer packaged goods, manufacturing, and robotics — particularly where regulatory nuance meets innovation.

Riley regularly represents both companies and investors in early- and late-stage financings, including SAFEs, convertible notes, preferred equity rounds, and secondary transactions. He also represents financial institutions (including BHCA-regulated entities) and other strategic investors in structuring and executing strategic investments.

Riley has been recognized by Best Lawyers: One to Watch in America® for Corporate Law (2026).

• Private companies across a range of matters, including Alethea, Exo Therapeutics, Kisbee Therapeutics, LogRocket, and Magnet Biomedicine.
• Numerous BHCA-regulated entities in multiple strategic investments.
• Financial and strategic investors, including Delta-v Capital, Novartis Venture Fund, and Wellington Management, among others, in early-stage, late-stage, and crossover investments and secondary transactions.

The above matters were handled prior to joining Sidley.

• Riley has represented Grist.org, a nonprofit-online magazine that provides environmental news and commentary.
• While in Bermuda, Riley spearheaded his firm’s adoption of a local nature reserve and acted as pro bono counsel for a Bermudan art gallery.