How the fair-price guard works
A tokenized share should cost about the same as the real share. It often doesn't, especially at night and on weekends, when the token keeps trading but the US market is shut. Anchor measures that gap, compares it with what's normal, and tells you when it's unusual.
Within the normal range for this hour. Buy as usual.
Cheaper than it usually trades. A good moment if you were buying anyway.
Far above normal. You have to confirm before buying.
The real price, from Pyth on Solana
The fair value comes from Pyth's US equity feeds (e.g. Equity.US.AAPL/USD). Anchor reads them directly from Pyth's price accounts on Solana, the same verified accounts a smart contract would read. It uses Pyth's confidence interval as well as the price, and you can verify any price on Solscan.
The token's price, from the market
The token price is the midpoint of a live $100 buy quote and the matching sell quote on Jupiter. That is what you could actually trade at. A pool's “last trade” price bounces between buy and sell prints and would create fake premiums.
xStocks reinvest dividends by raising a Token-2022 multiplier, so one raw AAPLx is slightly more than one share. Anchor reads the multiplier from the token mint.
Compare with what's normal for this hour
A 30-day hourly history of the premium, from the token's main pool and the US-listed stock, sets what's normal. Regular and extended hours get separate baselines. Anchor uses hourly averages rather than single trades, and the median and MAD rather than the mean, so one bad print can't distort the baseline.
σ also includes Pyth's live confidence interval. When publishers disagree, Anchor is slower to call a price unusual.
Widen the range while the market sleeps
When the US market is closed, the “real” price is the last trade, and the true value may have drifted since. The fair range grows like a random walk, with the square root of the hours since the last trade.
Judge it from a buyer's side
- Fair: within ±2σ of normal.
- Discount: 2σ or more below normal. Good news for a buyer.
- Pricey: 2–3σ above normal, or the swap itself costs more than 0.5%.
- Wait: 3σ or more above normal. You have to confirm before buying.
Before you sign, Anchor prices your actual Jupiter quote the same way. It separates the token premium from the swap's spread and price impact, and shows what that means in dollars.
Leave a receipt on-chain
Each buy carries a Solana memo in the same transaction as the swap. The guard's decision is therefore public and permanent, and anyone can check it. The Activity tab reads these memos directly from the chain.