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XL Batteries, Inc.

Develops long-duration flow batteries for grid operators, data centers and industrial users.

Updated Nov 10, 2026·Latest SEC filing Jul 14, 2026·Suggest an edit

About XL Batteries

XL Batteries is a private company based in Marlborough, Massachusetts. It has reported $36,142,646 raised in four offerings on Form D since September 2022. Its chief executive is Thomas Sisto.

Funding Rounds (SEC Form D)

First saleFiled with SECAmount soldInvestorsAvg. checkTermsFiling
Jun 30, 2026Jul 14, 2026$12,964,901of $25.0M target32$405KEquityRule 506(b)Form D ↗
Aug 6, 2025Aug 20, 2025$7,499,996of $9.9M target1$7.4MEquityRule 506(b)Form D ↗
Apr 22, 2024May 3, 2024amended Jul 23, 2025$7,674,872fully sold27$284KEquityRule 506(b)Form D/A ↗1 earlier filing
Aug 24, 2022Sep 7, 2022$8,002,877of $10.0M target13$615KEquityRule 506(b)Form D ↗
Total, four offerings$36,142,646

First sale is the date the first investor in the offering committed to invest. Companies must file Form D within 15 days of that date, so filing dates run later.

Leadership Team

Executive officers and directors listed on XL Batteries's Form D filed Jul 14, 2026.

Thomas Sisto
Thomas Sisto
Co-Founder & CEO, director
JS
Jeffrey Smith
Director
Also a director at Lightmatter and Tilt Five.

Earlier filings also listed Saif Qazi (director, last listed Aug 2025).

Sources

  1. SECXL Batteries, Inc. Form D, filed May 3, 2024
  2. SECXL Batteries, Inc. filing history
  3. CompanyXL Batteries contact
  4. CompanyAbout XL Batteries
  5. CompanyXL Batteries team
  6. CompanyXL Batteries wins 2026 BloombergNEF Pioneers Award