The central question: measured against what
It is usually skirted, and it decides everything. Almost everything on exchanges is quoted in USDT, so the easy move is to treat USDT as the dollar. But USDT is not the dollar: it routinely trades at 0.9996–0.9998.
Measure from it and every second coin shows a deviation of exactly that size, which does not exist. The real dollar has to come from where it exists: Coinbase and Kraken list pairs against live USD with bank funding. Those give the USDT rate, and everything else converts through it. That is how our page is built, and the rate being measured from is shown on the board.
Which coins count as stablecoins
Only those with a stated one-to-one peg. Yield-bearing wrappers — sUSDe, USDY, stUSDT, sDAI — do not belong: they appreciate by design as interest accrues, so their "deviation from the dollar" is the holder's yield, not a broken peg. Listing them beside real stablecoins misleads.
Three ways to earn
Across venues. The coin is cheaper on one platform and dearer on another: buy there, transfer, sell here. The catch is the transfer — withdrawals cost money, and at spreads of hundredths of a percent the fee eats everything. A real example from our data: USDP was 0.41% off peg, the cross-venue spread gave 0.08% on an executable size of 825 dollars — 66 cents of profit against a 5 dollar withdrawal fee. Net negative, despite the largest depeg on the list.
Waiting for the peg. Buy below a dollar and wait for recovery. No transfer needed, but you must know why it slipped: a temporary demand imbalance recovers in hours; problems with the issuer's reserves never do.
Redeeming with the issuer. The most reliable and the least accessible: the issuer undertakes to buy back at a dollar. In practice that means an account with them, document checks and usually a size upwards of a hundred thousand. For an individual this route is generally closed.
Telling noise from an event
Up to 0.02% is ordinary scatter — the peg is working. Between 0.02% and 0.1% is a visible imbalance, usually temporary. Above 0.1% is a reason to find the cause before buying: there is almost always news behind it, and sometimes the news is about reserves.
Each coin is labelled with its issuer, and that is not decoration: behind one ticker stands a specific company with specific assets, and a real depeg always starts with doubts about them.