Who pays the most property tax in Williamson County? (DRAFT – not published)

In short

• The 10 biggest taxpayers held about $4.7 billion of taxable value in 2025. That is about 3.6% of the county’s $130.1 billion total.¹
• Samsung Austin Semiconductor was first, with about $1.5 billion. It was not on the 2016 list.¹
• In 2016 the top 10 held about 2.7% of the total. Only two names are on both lists: Dell and Oncor.¹

Numbers marked “our math” are our estimates, not official figures. The notes show the inputs and the steps.

How it works

• Each year the county’s audit lists its 10 biggest property taxpayers. It shows this year and nine years ago.¹
• The values are taxable values. They are after the appraisal review board’s changes and exemptions.¹
• How we name owners. We name an owner only when it is a well-known company or a public body. We leave out any owner that is or could be a person, a family trust, or a small company tied to a person. We describe those owners by type instead.²
• A city can be on the list. The City of Round Rock is second. The audit does not say which property that is.¹

What the numbers show

Rank (2025)	Taxpayer	2025 taxable value	Share of county value
1	Samsung Austin Semiconductor	$1,525M	1.17%
2	City of Round Rock	$577M	0.44%
3	Dell Computer Holdings	$452M	0.35%
4	Oncor Electric Delivery	$423M	0.32%
5	Apple	$360M	0.28%
6	ZT Systems	$294M	0.23%
7	Atmos Energy	$275M	0.21%
8	A limited liability company (property type not given)	$270M	0.21%
9	Linde	$256M	0.20%
10	Citicorp North America	$229M	0.18%
	Top 10	$4,660M	3.58%

Source: Williamson County annual financial report, fiscal 2025, “Principal Property Taxpayers.” Rounding is ours.¹

• In 2016, Dell was first, at about $298 million. The top 10 held about $1.3 billion out of $47.4 billion.¹
• The county’s total taxable value grew about 2.7 times from 2016 to 2025 (our math).¹³
• The 2016 second-place owner is on the 2025 list under a new name. The audit gives the former name. It is a limited company, so we do not name it.¹²

The other side

• The top 10 hold a small share. Even together they carry less than 4% of the county’s value. Homes and other owners carry the rest.¹
• Value is not the same as tax paid. The county gives some owners tax breaks under state law. Its abatement program gave up about $3.1 million in fiscal 2025. The audit does not say which owners got them.⁴
• One name can stand for many parcels. Each line adds up all the property the owner has in the county.¹

Changes to this page

• Nov. 2, 2026: Rewrote the questions to ask so each is open, neutral and addressed to the public body.
• Nov. 2, 2026: We set one rule for naming property owners and applied it here. See the note on how we name owners.
• Nov. 2, 2026: We described the county’s tax breaks in the audit’s own terms.

Questions to ask

• How much of the top owners’ value is under a tax deal, by the appraisal district’s records?
• Which city-owned property is taxed, and why, by the appraisal district’s account?

What we still don’t know

• What each owner actually paid. The table shows value, not tax bills.
• The top taxpayers inside each city or school district. See property by school district for value by district.

Footnotes

1. Williamson County, Texas, Annual Comprehensive Financial Report for fiscal 2025, statistical section, “Principal Property Taxpayers, Current Year and Nine Years Ago” (p. 165), from the county tax assessor-collector and the Williamson Central Appraisal District. Public copy: https://emma.msrb.org/P11938140.pdf (MSRB EMMA). ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹²

2. Our naming rule, used on every page that lists property owners: we name a business only when it is a recognizable company or a public entity. Owners that are, or could be, individuals, family trusts or small LLCs or partnerships tied to a person are not named; we describe them by property type when the source gives it, or by legal form when it does not. No person is named on this page. ↩ ↩²

3. Our math. Total taxable value 130,112,257,856 ÷ 47,417,522,347 = 2.74. Top 10 share 3.58% (2025) and 2.69% (2016), from the table. ↩

4. Same report, Note 14, “Tax Abatements”: rebates under Chapter 312 of the Tax Code; taxes abated in fiscal 2025, tax abatement program $3,100,219. ↩