Read the regime. Move on the signal.

Two filters, one list

Volume tells you something is happening — attention, positioning, a catalyst. Regime tells you which way the odds lean. Neither is enough alone: a volume spike can be a blow-off top, and a quiet uptrend with no participation rarely goes anywhere.

regimefox looks for the overlap, and gates the whole thing behind the health of the broader market. Four steps run in order every morning.

Is the market itself bullish?

Before a single stock is examined, regimefox classifies the S&P 500 into one of three regimes. Buying volume breakouts works far better when the tide is coming in. When the market is not in a confirmed Bull regime, candidates still surface but are marked blocked — a reminder not to chase in a hostile tape.

The gate uses the regime state only. The market's structural odds of staying bullish top out around 72%, so the stricter per-stock probability bar would block entries even in healthy bull markets. The state alone is the signal.

How a regime is defined

Every stock — and the market itself — is labeled each day into one of three states, from its trailing 20-day return against a ±5% band.

From labels to probabilities

Those daily labels form a sequence. regimefox builds a Markov transition matrix from that history — the empirical odds of moving from any state today to any state tomorrow. Read the row for the current state and you get tomorrow's regime probabilities.

The relative-volume scan

For every stock in the universe, regimefox computes relative volume — each day's volume against that stock's own recent baseline, so a sleepy utility and a heavily-traded mega-cap are judged on the same scale.

Over the last five trading days, regimefox counts how many cleared 1.5× normal volume.

The per-stock bull filter

Each volume candidate gets its own two years of history pulled, its own regime labels computed, and its own transition matrix built. To pass, a stock must clear two conditions at once.

1 · In a bull regime

Its current state must be Bull — trailing 20-day return above the +5% band.

2 · Likely to stay

P(Bull tomorrow) must exceed 80% — a high bar that filters out fragile, about-to-roll-over trends. Names that had volume but fail here aren't dropped silently: they print as rejections, with the reason.

Confirmed vs. watchlist

Everything that passes the bull filter is sorted into two tiers by how strong its volume signal is.

Each name also carries its sideways/bear probabilities, bull-regime age, and day-by-day RVOL trend. See the live screener →