The companies which have signed the registration form for the TC39 Royalty Free Technical Committe (TC) are the following:
- Adobe*
- Agoric Systems
- Alibaba
- Apollo Graph, Inc.* (formerly Meteor Development Group)
- Apple
- Beijing Bytedance Network Technology Co., Ltd.
- Bloomberg
- Bocoup*
- Cloudflare, Inc.
- Coinbase, Inc.*
- Consensys Software, Inc. (Ecma membership to be voted upon at the June 2025 General Assembly)
- Datlas, Inc.
- Deno Land Inc.
- Dojo Foundation*
- Evernote*
- Functional Software, Inc.
- GoDaddy.com*
- HeroDevs
- Huawei
- IBM
- Igalia, S.L.
- Imperial College London
- Indeed, Inc.*
- Indiana University
- Inria
- Intel*
- JetBrains
- Leiden University*
- manabo* (formerly SATT AI Lab)
- Meta (formerly Facebook)
- MetaMask*
- Microsoft
- Moddable Tech, Inc.
- Mozilla Foundation
- npm, Inc.*
- OpenJS Foundation
- Oracle America, Inc.
- Oramasearch Inc.
- Pax Andromeda (formerly RunKit, Inc.)
- PayPal (ex eBay)*
- Qihoo (360)
- Record Replay
- Rome Tools, Inc.*
- Salesforce.com
- ServiceNow Inc.
- Shopify Inc.
- Sony
- Stripe, Inc.*
- Sujitech
- Tilde Inc.*
- Tencent*
- Turing School of Software & Design*
- Twitter*
- University of Bergen
- University of Turku
- Vercel
- Vrije Universiteit Brussel*
- Yahoo!*
- Zalari GmbH
* Not anymore Ecma member