Prices and daily averages
Yesterday uses three prices. Each has a separate job.
| Name | Short name | What it does |
|---|---|---|
| Yesterday’s reference | K | The fixed comparison price for today’s contracts |
| Entry execution price | S | The actual effective conversion price for a fill |
| Tomorrow’s average | H | The price used to divide the funds at settlement |
The planned protocol average
Section titled “The planned protocol average”The selected design uses a time-weighted average price, or TWAP, over the whole UTC day. A reported price counts for the time it remains in effect.
For a simple illustration, suppose a valid reported price is 80,000 for six hours and 84,000 for eighteen hours. The daily time-weighted average is 83,000. The second price counts three times as much because it covers three times as long.
Every second of the 86,400-second day must be covered. The planned oracle adapter uses validated Chainlink history. An oracle is the system that provides outside price data to a smart contract.
Base-specific history, stale-data rules, outages, finalization, and other integration details still need verification. This oracle is not a deployed trading service today.
The public website uses a different method
Section titled “The public website uses a different method”The landing page uses Coinbase BTC/USD data. Its daily reference is the average of all 288 five-minute closing prices in a complete UTC day.
That is a sampled daily average. It is not the planned duration-weighted protocol average, a live BTC/USDC conversion, or a settlement price for real contracts.
The price currency also matters: Coinbase’s source is BTC/USD. The educational displays do not prove that one USDC will always trade for one U.S. dollar.
Freshness and missing data
Section titled “Freshness and missing data”The landing service normally collects a spot observation every 30 seconds. An observation becomes delayed after two minutes and unavailable after fifteen minutes. Illustrative quotes are hidden once the observation is too old for them.
A missing five-minute candle makes a daily reference incomplete. The service does not fill the gap with a guessed value.
An estimate is not an execution
Section titled “An estimate is not an execution”The public calculator shows estimates. Future real execution must use the actual tokens received after conversion costs. That amount determines funding and must be consistent with the execution price used for eligibility and q.