The honest answer has two parts. The visible part (whether the S&P 500 is near its record or in a correction, above or below its long‑term trend, calm or volatile) is public, and the market risk check below shows it, updated after every trading day. The regime call (whether the backdrop behind those prices favours taking risk or protecting capital) needs a model, because price can look fine while conditions underneath deteriorate, and the reverse.
“Risk‑on” and “risk‑off” describe that backdrop. In a risk‑on market, investors reward risk: growth stocks, high‑beta stocks and leveraged funds lead, and pullbacks get bought. In a risk‑off market, investors pay for safety: correlations between stocks rise, falls are deeper, and cash‑like assets are the only reliable shelter. Between them sits a neutral or transition phase, where signals disagree. More background: what a market regime is and the full portfolio protection guide.