A normal Bitcoin UTXO is limited in what it can express. Bitcoin Script can enforce spending conditions, but it was not designed to maintain the flexible application state required by financial applications. Arch extends this model by creating Programmable UTXOs. Here’s how: → A Programmable UTXO combines a real Bitcoin UTXO with an Arch account containing application state and program logic. → Instead of representing only an amount of spendable BTC, the UTXO can now interact with applications built through the ArchVM. → That BTC could be used as collateral in a lending market, supplied as trading liquidity, or governed by another financial program. → Arch tracks the application state, executes the relevant instructions, and verifies the resulting state transition through its validator network. → When the underlying BTC needs to move, Arch validators sign the resulting Bitcoin transaction and settlement occurs on Bitcoin. The BTC is not recreated as an ERC-20 token or synthetic representation on another network. The foundation remains a real Bitcoin UTXO. Arch makes that UTXO programmable. Bitcoin created the UTXO. Arch turns it into programmable financial infrastructure.