Persefoni's SEC-rule bet: $180M for carbon accounting as US mandate collapses

Cloud software that calculates, audits and reports companies' greenhouse-gas footprints — an 'ERP for carbon data' for enterprises, banks and asset managers.

Mandatory climate disclosure (SEC, EU CSRD) would make carbon accounting the biggest compliance market since Sarbanes-Oxley — firms need software, not spreadsheets.

Founded Jan 2020; $101M Series B (Oct 2021, Prelude + TPG Rise), $50M Series C-1 (Aug 2023, TPG Rise), $23M Series C extension (2025) — over $180M total.

Co-founders Kentaro Kawamori and Kim Stroh incorporated Persefoni AI Inc. in Tempe, Arizona in January 2020 as the SEC's climate-disclosure push and EU CSRD drafts gathered force. Kawamori told TechCrunch in Oct 2021 that carbon and climate disclosures would be 'the biggest compliance market since the advent of Sarbanes Oxley and GDPR.'

The bet attracted capital: a $101M Series B in Oct 2021 led by Prelude Ventures and TPG's Rise Fund, then a $50M Series C-1 in Aug 2023 led by TPG Rise with an AI copilot, PersefoniGPT. The SEC adopted its climate-disclosure rule on March 6, 2024 — mandating material climate-risk and Scope 1/2 emissions reporting — then stayed it on April 4, 2024 while challenges were consolidated in the Eighth Circuit.

Still operating, but the core US bet collapsed: the SEC voted in March 2025 to stop defending the rule and proposed its rescission in May 2026. Persefoni pivoted to the EU and California — shipping CSRD-native reporting and SB 253/SB 261 support in 2025, acquiring Diligent's carbon-accounting customer base, and passing 8,000 Pro users.

The SEC's March 2022 proposal and CSRD created a dated, concrete demand event: thousands of filers would need auditable emissions data, and Persefoni built the accounting-grade product first.

It wedged into financial institutions, whose financed-emissions deadlines under PCAF/TCFD came earliest — yielding four of top-10 PE firms and four of the world's 20 largest banks as clients.

It positioned against spreadsheets and consultants as an auditable 'ERP,' arguing proprietary methodologies would fail audit at scale — a story that TPG Rise, EDF and SMBC funded to over $150M.

When the US rule was stayed and later abandoned, a multi-jurisdiction platform design let Persefoni shift to CSRD and California instead of dying with the SEC rule.

A bet on a pending rule is a bet on politics: $180M rode the SEC climate mandate, and a stay erased the US market overnight; survival came from CSRD and California. Diversify the regulatory thesis.

As of 2026-09-02 Persefoni is live and independent: it raised a $23M Series C extension in 2025, acquired Diligent's carbon-accounting customer base, and reports 8,000+ Pro users across 100+ countries, including Xerox, General Atlantic and Pleo. Its 2025 product line centers on CSRD-native reporting and California SB 253/SB 261 support. The SEC's proposed rescission remained pending in mid-2026, so the US mandate it was founded on is effectively gone; the business now rests on EU and state rules.