Stacks is a protocol foundation firm based in Global that stacks is a bitcoin layer that brings smart contracts, defi and decentralized apps to bitcoin, secured by the bitcoin network. the ecosystem is supported by the stacks foundation, which funds r&d, grants and governance, and by hiro, which builds developer tooling. its sbtc asset lets users bring native bitcoin into smart contracts. the nakamoto upgrade and sbtc launched in 2024. They serve clients in Global. Stacks is listed on The Token Playbook's vetted provider registry at thetokenplaybook.com/registry/stacks.