Overview

TaxProper was a Chicago-based property tax technology company founded in May 2019 by Thomas Dowling and Geoff Segal through Y Combinator's Summer 2019 batch. The company launched as a consumer-facing tool that automated property tax appeals for homeowners, then executed a deliberate pivot to an enterprise SaaS platform serving institutional real estate operators — managing tax payments, forecasting, and appeals across large portfolios nationwide.

The pivot worked. By the time Opendoor Technologies acquired TaxProper on November 4, 2022, the company was servicing 115,000+ properties worth over $35 billion and processing more than $1 billion annually in property tax payments — all on $2.15 million in total capital raised.^[1]

Opendoor acquired TaxProper for an 8-figure sum, making it a textbook example of capital-efficient execution in a niche vertical where regulatory complexity served as a durable moat.^[2] The founding team subsequently departed Opendoor and launched FullSeam, accepted into YC's Winter 2026 batch — their second consecutive YC company.

Founding Story

Thomas Dowling arrived at Oxford in 2018 as a Rhodes Scholar, having graduated from the University of Illinois Urbana-Champaign with a degree in history and political science.^[3] Before Oxford, he had served as a Municipal Finance Policy Advisor on Chicago Mayor Lori Lightfoot's transition team — a role that gave him direct exposure to how local governments set, contest, and collect property tax assessments.^[4] That policy background was not incidental to TaxProper's founding; it was the origin of the insight.

His co-founder, Geoff Segal, brought a complementary technical skillset. Segal had worked as an actuarial statistician and research analyst at State Farm, where he built quantitative models of property risk and value — precisely the kind of statistical machinery needed to compare assessed values against market comparables at scale.^[5] Dowling has described Segal as "another classmate from Illinois," suggesting the two knew each other before Oxford and reconnected around the idea.^[6]

The founding insight was structural: property tax assessments are frequently inaccurate, the appeals process is well-established and legally accessible, but the friction of filing — understanding deadlines, gathering comparable sales data, completing county-specific paperwork — was high enough that most homeowners never bothered. Incumbent property tax attorneys existed but charged contingency fees that made them economically viable only for high-value commercial properties. The consumer market was essentially unserved by software.

Dowling and Segal applied to Y Combinator while Dowling was still at Oxford. The application succeeded. As Dowling later recalled: "I started working on a project that eventually grew into a software startup called TaxProper with another classmate from Illinois. We were accepted into a startup accelerator called YCombinator halfway through my first year at Oxford."^[7]

TaxProper was incorporated in May 2019 and participated in YC's S19 batch, receiving the standard $150,000 in batch funding.^[8] The company launched publicly at YC's S19 Demo Day in August 2019, pitching the B2C appeal automation product to investors. The founding team's domain pairing — municipal finance policy expertise plus actuarial statistical modeling — was unusually well-matched to a problem that required both regulatory navigation and quantitative accuracy.

Dowling was subsequently recognized on the Forbes 30 Under 30 list and appointed by Illinois Governor JB Pritzker to the Illinois Student Assistance Commission, reflecting the public profile he built during TaxProper's growth.^[9]

Timeline

• May 2019 — TaxProper founded by Thomas Dowling and Geoff Segal in Chicago, IL.^[10]
• Summer 2019 — Accepted into Y Combinator S19 batch; receives $150K standard batch funding.^[8]
• August 2019 — TaxProper pitches at YC S19 Demo Day, presenting the B2C property tax appeal automation tool to investors.