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Sean Semmler
U.S. Expansion Counsel
Corporate

D336-455-2400

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  • The Market-Leading U.S. Expansion Group

    Sean helps lead Wilson Sonsini’s U.S. Expansion Group, advising tech and life sciences companies from all over the world on raising U.S. capital and expanding their businesses into U.S. markets.

  • A Leader in Legal Tech

    Sean specializes in developing tools to automate various legal tasks within the firm.

  • Entrepreneurial Experience

    During his undergraduate studies, Sean co-founded a start-up based in the Research Triangle area. Sean interned at an artificial intelligence company in San Francisco, California, before coming to work at Wilson Sonsini.

  • Tech Fluency

    Sean is knowledgeable in all areas of emerging technology, including blockchain, artificial intelligence, and fintech.

Sean Semmler is the lead U.S. Expansion Counsel at Wilson Sonsini Goodrich Rosati, where he advises start-ups, scale-ups, and other high-growth companies from all over the world throughout their U.S. lifecycle, including their U.S. launch, expansion, fundraising, partnerships, M&A, and IPO. Sean has advised hundreds of clients on a range of issues, including entity formation, EIN applications, regulatory compliance, and ongoing corporate governance.

Sean is also experienced in venture capital and M&A. He has counseled emerging growth companies and venture firms from all over the world. Sean has worked on dozens of M&A transactions in the past few years, advising companies on both the buy and sell sides of international transactions, strategic mergers and business combinations, and business and asset acquisitions.

Experience

Sean Semmler is the lead U.S. Expansion Counsel at Wilson Sonsini Goodrich Rosati, where he advises start-ups, scale-ups, and other high-growth companies from all over the world throughout their U.S. lifecycle, including their U.S. launch, expansion, fundraising, partnerships, M&A, and IPO. Sean has advised hundreds of clients on a range of issues, including entity formation, EIN applications, regulatory compliance, and ongoing corporate governance.

Sean is also experienced in venture capital and M&A. He has counseled emerging growth companies and venture firms from all over the world. Sean has worked on dozens of M&A transactions in the past few years, advising companies on both the buy and sell sides of international transactions, strategic mergers and business combinations, and business and asset acquisitions.

Focus Areas
Recent Insights
Client Highlights
Wilson Sonsini Advises Versori on Acquisition by Avalara
On February 27, 2026, Avalara, the leading provider of cloud-based tax compliance automation software, announced that it acquired Versori Group, an integration platform company specializing in automated connector development powered by agentic AI. Wilson Sonsini Goodrich & Rosati advised Versori on the transaction.
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Client Highlights
Wilson Sonsini Advises Phare Health on Acquisition by R1
Wilson Sonsini’s London-based M&A team advised Phare Health Ltd, a healthcare technology company building AI-native solutions for inpatient coding and clinical documentation improvement, on its sale to R1 (an industry leader in managing and intelligently automating healthcare revenue management).
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Recent Events
WSGR Events
U.S. Corporate Transparency Act
On January 1, 2024, FinCEN’s new BOI reporting requirements went into effect. For the first time, many U.S. companies must now affirmatively disclose information about their officers, directors, and key stakeholders to the Financial Crimes Enforcement Network (FinCEN), the anti-money laundering arm of the U.S. Treasury Department. Companies created or registered to do business in the U.S. prior to January 1, 2024 have until the end of this year to file their initial BOI report. Penalties for noncompliance can include fines up of to $500 per day and up to two years in prison.
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WSGR Events
College for Clients Series: Overview of FinCEN’s Beneficial Ownership Information Reporting Requirements and What You Need to Know
Wilson Sonsini is pleased to host Overview of FinCEN’s Beneficial Ownership Information Reporting Requirements and What You Need to Know, the first webinar in the 2024 College for Clients Series. The College for Clients Series is designed to help our clients address and manage some of the fundamental legal issues facing them today.
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