Investor Profile: S3 Ventures — Thesis, Cheque Size & How to Apply

S3 Ventures is an Austin based venture firm founded in 2005 that describes itself as the largest and longest serving venture capital firm born in Texas and investing nationwide.

Investment thesis

S3 backs visionary founders with the patient capital and true resources needed to build extraordinary, high impact companies. It seeks entrepreneurs solving billion dollar business problems in unique and transformative ways, and companies improving the human condition through medical devices and software.

Sectors and stages

S3 leads Seed, Series A, and Series B rounds. Its two stated focus areas are business software and healthcare technology. Business software covers software applications, IT infrastructure, developer tools and platforms, hardware, and other technology driven products and services for business needs.

Fund size and cheque size

S3 announced Fund VIII at $250 million in December 2025, marking its twentieth year, and said the firm then managed over $1 billion in assets. Initial investments range from $500,000 to $15 million or more, with capacity to invest over $25 million over the life of a company.

Notable portfolio

The firm's portfolio list includes Alkami Technology, which went public on NASDAQ; Levelset, acquired by Procore; Favor, acquired by HEB; Interplay Learning, focused on skilled trades training; Atmosphere TV, a business video platform; Hydrolix, a data platform company; and QbDVision, a life sciences software company. Healthcare names on the firm's list include Alleviant, Flex Vascular, and Braincheck.

Partners and team

S3 was founded by Brian R. Smith, its Founder and Managing Director. In the Fund VIII announcement, Charlie Plauche is named as a General Partner, and Eric Engineer and Aaron Perman were promoted to General Partner, bringing the entirely Austin based team to 12 people.

Programs and perks

S3 runs a public Startup Toolbox with founder resources including a SaaS operating model, term loan calculator, stagger charts, cash management tools, sales quota and forecast workbooks, a capitalisation table template, an option grants workbook, a unit economics workbook, and a Starter Kit for Texas Founders.

How to apply for funding

S3 does not publish a guaranteed open application portal, so the strongest route is a warm introduction through a portfolio founder, a Texas ecosystem contact, or another investor, followed by a concise pitch through the firm's official website at s3vc.com.