Bitcoin News posted on the X platform that Strike has launched the Stacks Bitcoin savings envelope system, allowing users to divide their holdings into up to 5 custom-named buckets, each supporting fee-free regular purchases. Transfers between Stacks and the main balance are fee-free and unlimited, but funds must be transferred back to the main balance before withdrawal.Strike has added an interest of 3.6% on USD cash balances, with interest paid in Bitcoin, and the related assets remain stored in Strike's multi-signature cold storage.