Bitcoin (BTC) is 8.8× the size of Tether (USDT) by market capitalisation. Their daily returns move loosely together (correlation 0.40 across 58 shared trading days). BTC has been the more volatile of the two, at 44% annualised against USDT's 1%.
BTCUSDT
0.40over 58 shared trading days
Measured on daily returns rather than on prices. Two assets that both simply trend upward score near 1.0 on raw prices whether or not they move together, so returns are what answer the question people mean by correlation.
| Metric | BTC | USDT |
|---|---|---|
| Max drawdown (400d) | -53.0% | -0.2% |
| Risk-adjusted return (90d) | 0.51 | -0.03 |
| Best 30 days (past year) | +26.8% | — |
| Worst 30 days (past year) | -32.9% | — |
Relative strength over 90 days: BTC outperformed USDT by 23.2% — measured on the BTC/USDT ratio, so it holds regardless of market direction.