The Stacks community approved SIP-045, the Bitcoin Staking upgrade, with more than 99% of votes in favor, said Stacks co-creator Muneeb Ali, and set up a hard fork, targeting around July 29, at approximately Bitcoin block 907,740.
The upgrade, formally “PoX-5: Bitcoin Staking and Emission Schedule Alignment,” lets participants lock in $BTC into a time-bound contract on Bitcoin’s base layer – under their own keys – and link it to locked $STX to earn returns, paid in bitcoin. A companion proposal, SIP-044, which brings Clarity 6 and new stakeout conditions, was passed alongside it. Voting opened on July 6; hard-fork votes require at least 80% approval of stacked $STX.
“Bitcoin is the world’s most trusted asset precisely because of the design and security principles on the L1,” Ali said when the Bitcoin Staking whitepaper was published in May. “Holders can now earn returns that herald $BTCwithout trust, while their Bitcoin remains exactly where it belongs.”
How the mechanism works
Stakers fund a timed UTXO on Bitcoin with OP_CHECKLOCKTIMEVERIFY, linking it to a $STX commit equal to at least 5% of the bond, and commit for approximately six months. The Stacks contract verifies the lock on the Bitcoin side with an SPV proof – not a custodian or trusted bridge. The proceeds come from the $BTC that miners already offer via Proof of Transfer: paired bonds receive a target of approximately 3% APY $BTC, $STX-Only stackers take 85% of the surplus, and 15% build up a reserve that buffers shortages. There is no cutting; the principal amount is fully refunded when the time slot expires.
The bootstrap phase limits capacity to 3,000 $BTCmanaged by the Stacks Endowment with whitelisted partners and approximately 10% open to pools. A public testnet went live this week and a “Genesis Bond” is planned for late August.
SIP-045 also reverses the April emissions reduction, thereby restoring greenhouse gas emissions $STX coin base up to 1,000 $STX per Bitcoin block of 500 – a meaningful increase in supply, bundled with the staking mechanism.
Yield without leaving Bitcoin
Stacks has distributed more than 4,200 $BTC – about $500 million – in stacking rewards since Proof of Transfer went live in 2021, and its sBTC-bridged assets hold about $186 million, per DefiLlama, down from a peak of $545 million in the first quarter $BTC‘The price fell.
The voting result did nothing for the token. $STX is trading at $0.144, down 13% in 24 hours, according to CoinGecko, significantly underperforming Bitcoin’s 1.9% decline.