Falling-knife check — don't buy a bounce that isn't coming

A bullish signal in a stock that's still falling is the most common way to lose money on reversal setups. Here's how to screen them out — and which signal type is most exposed.

The trap

"Falling knife" means a stock still in free-fall. Your signal says oversold; the decline continues anyway because the driver that pushed price down — earnings miss, sector rotation, regulatory shock — is still active. You buy the bounce; there is no bounce.

The engine reads price and momentum. It does not read news or marco. The falling-knife check is how you close that gap.

Which signal is most exposed

• Mean Reversion Signal — primary target of the check. Fires on a divergence between price and momentum during a decline. That reading is derived from price alone, so it cannot see that tomorrow brings a guidance cut. Run the check every time Mean Reversion fires in a drawdown.
• Trend Reversal Signal — less exposed, still worth checking in steep falls. Fires on a regime flip — a structural event, not just a stretched reading. It is more robust than a pure oversold signal, but a flip can still fake out when the macro backdrop keeps deteriorating. Run the check if the drawdown is brutal or you don't know the story behind it.

The check — three questions

1. Why did it fall? Check recent news on the ticker. Earnings miss, guidance cut, downgrade cluster, regulatory action, sector rotation, macro shock, governance issue. If you cannot name the cause, you don't know what you're betting against.

2. Is the cause still active? Bad news still unfolding — analysts still cutting, more guidance revisions expected, open investigation — means the bounce is premature. Signs the cause may be spent: the catalyst is already absorbed in price, negative revisions have peaked, insider buying at scale, valuations compressed versus peers.

3. Is there bottom structure on the chart? Multiple tests of the same low, higher lows forming, a capitulation-volume spike — all signs sellers are exhausted. Price still cascading with no structure → no trade, no matter how strong the signal looks.

Qualify or skip

Take the trade if at least one of these holds:

1. Fundamental stabilisation — recent earnings beat, guidance raise, meaningful cost reset, or insider buying at scale.
2. Forward catalyst — upcoming earnings with raised expectations, M&A rumour, policy or regulatory change, product launch.
3. Exhausted driver (Mean Reversion only) — clear evidence the drawdown's cause is spent and nothing new is on the horizon.

If none of the three is true, skip the signal.

Why this beats confluence

Three rules agreeing that a stock is oversold all measure the same thing — price structure. The real question is fundamental: is the cause still active? Only a news check answers that. Confluence filters noise inside the price series; the falling-knife check filters the world outside it.