Listed as a CPA in IRS public preparer records. Source: IRS PTIN FOIA extract (Feb 2026), retrieved October 23, 2026. https://www.irs.gov/pub/foia/foia-illinois-extract.csv No state license number is on file. Specialties are blank until this preparer claims the listing. CPA Seek does not contact preparers.

Catherine Mary O'Connor

CPA · Grant Thornton Advisors LLC

Downers Grove, Illinois 60515

Catherine Mary O'Connor, CPA in Downers Grove, IL

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Catherine Mary O'Connor, CPA in Downers Grove · CPA Seek