Key Concepts in Five Minutes

Ten ideas explain almost everything in these docs.

Tokenized stock: A token on Solana that tracks a US stock or ETF, issued by an approved issuer under its own terms. See What Tokenized Stocks Are.
Collateral and the pool: What you deposit to borrow. All collateral for one asset sits in one pool, and your position is a share of that pool.
Loan to value (LTV): Your loan divided by the value of your collateral. You can borrow up to 50%. A $10,000 position can carry a loan of up to $5,000.
Liquidation threshold and health factor: If your LTV rises past your asset's threshold (between 54.1% and 62.5%, depending on the asset), some or all of your collateral is sold to repay the loan. The health factor is the threshold divided by your LTV: above 1.00, the position cannot be liquidated; below 1.00, it can be. The app's safe zone is an LTV up to 35%.
Covered call: The right to buy a stock at a fixed price before a fixed date, sold by someone who owns the stock. Spout sells covered calls on each pool.
Premium: What the buyer pays up front for a call. It is kept whatever happens next. Premium is the main source of lender yield.
Strike and expiry: The strike is the fixed price; the expiry is the date the right ends. Spout sets strikes above the current price.
Assignment: If the stock finishes above the strike, the buyer exercises. The called shares are delivered from Spout's brokerage account at the strike, and Spout uses the strike proceeds to buy back as many shares as they cover. The shortfall is the move above the strike, which borrowers give up for that cycle.
Tranches: Lenders choose Senior (paid first, absorbs losses last) or Junior (gets most of the extra income, absorbs losses first).
Utilization: The share of lender USDC currently lent out. Borrowing pauses once 85% is lent, so new loans cannot use up the cash lenders withdraw from.

The Glossary defines every other term used in these docs.