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The Venture Codex

645 Ventures

335 Madison Avenue, 7th Floor, Suite A, New York, NY, 10017, United States

Overview

645 Ventures is an early-stage venture capital firm that partners with exceptional founders who are building iconic companies. We invest at the Seed and Series A stages and leverage our Voyager software platform to enable our Success team and Connected Network to help founders scale to the growth stage. Select portfolio companies that have reached the growth stage include Iterable, Goldbelly, Resident, Eden Health, FiscalNote, and Squire. We invest in four main areas: SaaS for the Second Wave, Citizen Professionals, The Engineering Value Chain Revolution, and Personalized Consumer Applications. You can read more here: https://645ventures.com/themes/ 645 Ventures has $200m+ in AUM and is growing fast with backing from leading institutional investors, including university endowments, funds of funds, and pension funds. We have over 35 active companies in our portfolio in the areas of enterprise SaaS, infrastructure software, and consumer technology. Several of our portfolio companies have been acquired by Google, Facebook, Expedia, and private equity firms.

Total investments
86
Lead investments
25
Investments · 12mo
20
Active investors
13

Sector focus

  • Finance
  • Financial Services
  • Venture Capital
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Investment portfolio

  • Rivo

    Participated · Seed · Aug 2026

    Rivo connects to users' existing bank accounts, monitors cash flow in real time, and automatically moves idle balances into higher-yield U.S. Treasury securities through its banking partner, Jiko, returning funds before bills are due. Users do not need to change banks, move money manually, or alter their behavior to receive higher yields. Rivo emphasizes handling edge cases—shifted pay cycles, early bills, shared accounts—drawing on a founding team with experience from Cruise, Amazon, Personal Capital, Mint, Capital One, JPMorgan Chase, Microsoft, and LinkedIn. The company launched out of beta and opened to the public concurrent with its seed financing. Rivo disclosed that treasury investments are provided by Jiko Securities and that securities in accounts are protected by SIPC up to applicable limits. The firm highlighted the scale of idle checking balances in the U.S. as context for its product but did not disclose revenue or user metrics in the announcement.

  • Ellis

    Participated · Seed · Jul 2026

    Ellis builds an AI-driven platform and agents to tackle fragmented workflows used by private credit managers, connecting documents, accounting data, and multiple software systems into a single interface. The system can flag data discrepancies and deploy agents to assist with portfolio monitoring, preparing reports, and month-end book-closing tasks. Ellis emphasizes integration with firms’ existing systems rather than replacing them, and it maintains a human-in-the-loop approach so material decisions remain with human experts. The company was founded by Ryan Williams, who previously co-created Cadre; Williams began work on Ellis in the year prior to the article. At emergence from stealth Ellis announced functionality and product goals alongside its $10 million seed raise from a syndicate of venture investors.

  • Fish Audio

    Participated · Seed · Jul 2026

    Fish Audio develops AI speech generation and speech-to-text models and offers both open-source releases and paid API plans for creators, teams, and enterprises. The company has launched five models in the last year—three of which are open-sourced—and its S2.1 Pro model is available only through its paid API. Fish Audio reports more than 8 million users and $21 million in annual recurring revenue, and its GitHub Fish Speech repository has over 31,000 stars. It offers paid monthly plans that unlock generation minutes and voice cloning features, and it also runs enterprise APIs used by companies including HeyGen, Sanas and Plaud. The startup plans to release an audio understanding model this year and is building a speech-to-speech model as part of its roadmap. Fish Audio has also implemented an automated takedown process and creator verification flows to address consent and licensing concerns around uploaded voices.

  • Upside

    Participated · Series A · Jun 2026

    Upside pairs dedicated Care Guides (licensed social workers and housing specialists) with an AI-supported housing orchestration platform and a proprietary affordable housing inventory database to identify, engage, and stabilize members. The company operates in 10 states and serves Medicaid, Medicare Advantage, D-SNP, commercial, and employer-sponsored populations. Upside reports 90%+ enrollment among referred members, more than half of members stabilized within 90 days, and up to 4x ROI within 12 months, alongside industry-leading member satisfaction. In the past 18 months it has secured partnerships with more than 17 national, state and regional health plans and is supporting four of the largest national payers. Upside plans to expand nationally, deepen its AI workflows for acuity stratification, housing matching, and case management, and scale Care Guide capacity and partner operations. Founded in 2020 and headquartered in Fort Lauderdale, FL, the company is positioning to grow across Medicaid, Medicare Advantage, and employer markets simultaneously.

  • AIVA

    Led · Seed · Jun 2026

    Founded in 2026 by Lucía Marí Sanguino and Paula Rodríguez Jou, AIVA develops a contextual AI and autonomous-agent–driven intelligence layer for hotels. The platform aims to help hotels understand guest behavior and property operations in real time to enable smarter decisions and improve guest experiences. AIVA says its technology also supports increasing ancillary revenue through personalized recommendations. The company is incorporated as a Delaware C-Corp and headquartered in New York. AIVA plans to expand its engineering team and accelerate product development with the new capital. The firm intends to deploy its technology across its initial hotel customer base as it scales commercially.

Team