Gerard O'Reilly

Co-Chief Executive Officer and Co-Chief Investment Officer, Dimensional Fund Advisors

FundDimensional Fund Advisors LP$551.84B

Gerard O'Reilly is co-chief executive and co-chief investment officer of Dimensional Fund Advisors. He has shared the CEO role with Dave Butler since 2017.

Funds

The funds Gerard O'Reilly runs, and what each reported holding in its latest 13F filing with the SEC.

Dimensional Fund Advisors LP$551.84BCo-Chief Executive Officer and Co-Chief Investment Officer3,221 positions · 13F as of Jun 30, 2026Largest positionsNvidia3.4%Apple3.1%Microsoft2.1%See the portfolio →

Snapshot

Known for

Running Dimensional's investment side as co-CEO and co-CIO

Worth knowing

He came to fund management from aerospace research rather than finance.

Role: Co-CEO and Co-CIO, Dimensional Fund Advisors