# Fixed Rates Open **Fixed Rates (PT)**, choose a market, then select **Buy**. The market header shows maturity and **Max PT APY**. That indicative market rate can differ from the quote for your chosen amount because execution includes liquidity, price impact and fees. Select an input token, enter an amount and review: * **Output**: the estimated PT received. * **Fixed Maturity Yield**: the estimated maturity proceeds minus input value, denominated in the underlying token. Its USD equivalent varies with the token's price. * **Fixed APR / APY**: the annualized quoted return. APY assumes compounding through future reallocation; the app does not automatically roll over matured PT. * **Slippage Tolerance** and **Min. received**: the permitted output tolerance and the smallest PT amount accepted by the transaction. * **Pool Fee** and **Price Impact** in **Details**: costs already reflected in the quote. The token's redemption rate determines the underlying amount at maturity. A loss in the underlying layer can reduce that rate; an IBT or wrapper output uses its own conversion. Read the [risk documentation](/docs/spectra/security/risk-documentation#negative-yield-risk). A zero or negative quoted fixed yield blocks **Buy PT** and explains why. Negative fee-inclusive fixed APY can occur even when spot implied APY is positive. The **above par** explanation applies when spot implied APY is negative. Try a smaller amount or inspect another market; compare the refreshed quote rather than relying only on the headline APY. A negative fixed-rate quote shows its maturity yield and a warning before connecting the wallet. *Example quote captured during a local app check. Amounts and rates change with the market.* Approve the input token if required, then confirm **Buy PT** in the wallet. Track the transaction through confirmation. At maturity, [redeem your PT from Portfolio](/docs/spectra/app-help/redeem-principal-tokens). Before maturity, [Sell PT](/docs/spectra/app-help/sell-principal-tokens) or [Burn PT+YT](/docs/spectra/app-help/withdraw-pt-yt) may be available. [Principal Token FAQ](/docs/spectra/the-basics/faq#principal-token-pt)