How Sprig works.

Sprig has one jar per target stock: NVDA, TSLA, SPCX, AAPL, GOOGL and SPY. Every jar saves in the same token, SGOV, the Robinhood Stock Token of a fund of US Treasury bills that mature within three months. SGOV's price rises slowly as the bills pay interest.

Depositing USDG swaps it into SGOV on Uniswap and records your deposit, your principal, in USDG. The jar keeps track of the total principal of all its savers and of the SGOV it holds.

A jar's SGOV is valued at the Chainlink price. Whatever it is worth above the total principal is interest. A harvest sells exactly that SGOV for USDG, keeps 10% for Sprig and a 0.10 USDG tip for the caller, and buys the jar's stock with the rest. The stock is shared among savers in proportion to their principal, from the moment it is bought.

Anyone can run a harvest; Sprig's keeper does it once a day when a jar has at least 1 USDG of interest. Every swap must fill within 1% of the Chainlink price or it reverts, so a pushed pool cannot be used against a jar.

Claim the stock bought for you at any time. Withdraw any part of your principal at any time: you receive your share of the jar's SGOV, swapped to USDG, or as SGOV directly with no swap. Any stock owed to you is sent with the withdrawal.

The swap in and out costs about 0.35% each way on $10,000 (a 0.05% pool fee plus price impact). With T-bill interest at a few percent a year, a jar works best over months.

The owner can list jars and set the fee (at most 20% of each harvest) and the tip (at most 1 USDG). It has no function that moves savings.

SGOV can fall in price; it depends on its issuer and on Chainlink. The stock a jar buys moves like any stock. The contracts are new and unaudited. Fork tests on Robinhood Chain mainnet save, harvest into NVDA, split between savers, claim and withdraw with the real tokens, feeds and pools.