What it is
A stablecoin trading meaningfully above or below the value it claims to hold.
Why it matters
A stablecoin is a promise to always be worth one unit. When the market stops believing the promise, the price tells you first. Small drifts are normal plumbing; large or persistent ones are the market pricing doubt.
How we read it
We read the live price against the peg and the size of what is circulating, because a one-cent wobble on a billion-dollar coin is a very different event from the same wobble on a small one.
What it cannot tell you
A momentary depeg on thin weekend liquidity is not a collapse. Size and persistence matter more than the instantaneous number.