> For the complete documentation index, see [llms.txt](https://docs.stacks.co/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.stacks.co/pox-5/actors/btc-protocol-bond-participants.md). # BTC Protocol Bond Participants Native BTC protocol bond participants lock BTC on Bitcoin L1 under their own keys and pair that position with locked STX on Stacks. In [PoX-5](/pox-5/glossary.md#pox-pox-4-pox-5-pox-6), they are usually [whitelisted](/pox-5/glossary.md#whitelist-and-whitelist-row) institutional partners with negotiated capacity, and they receive first-priority [Tranche 1](/pox-5/glossary.md#t1-t2-t3-waterfall-tranches) BTC yield if their [allocation](/pox-5/glossary.md#allocation-bond-capacity), L1 lock, and STX commitment remain valid. Registration is gated by full [BTC SPV proofs](/pox-5/glossary.md#btc-spv-proof): for each L1 lockup output, the participant submits the Bitcoin block header, the merkle inclusion path, the raw transaction, and the output index to `register-for-bond`. The contract verifies the header, the merkle proof, and that the output's script-pubkey matches the expected [P2WSH lockup script](/pox-5/glossary.md#lockup-script-p2wsh-lockup-output) derived from the participant's parameters before recording the membership. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.stacks.co/pox-5/actors/btc-protocol-bond-participants.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.