A statistical measure of how far price has strayed from its recent average — it can stay stretched for a long time during a genuine trend, unbounded unlike RSI.
Donald Lambert introduced CCI in 1980 to identify cyclical turns in commodity prices using statistical deviation.
Despite its name, traders adopted CCI for stocks, indices, and currencies just as readily as commodities.
The ±100 bands became popular overbought/oversold shorthand, inheriting the same persistence problem as RSI.
Serious use reads it alongside the prevailing trend, exactly like every other oscillator here.
CCI compares today's typical price to its recent average, scaled by mean deviation — unlike RSI, it has no fixed ceiling or floor.
In a genuinely strong trend, CCI can stay well above +100 for an extended stretch — exactly the same persistence problem as RSI.
CCI crossing back under +100 is worth a closer look, but only alongside trend context and price/CCI divergence does it become an actual signal.
Through that stretch, CCI stayed pinned well above +100 repeatedly, while price kept climbing well past where a threshold-seller would have exited.
Near that top, CCI crossed back under +100 while also diverging against price — the combination that preceded the decline, not the cross alone.
Price is in a strong, sustained uptrend. CCI reads +240 with no divergence. A trader shorts immediately. Sound?
CCI crosses back under +100 at the same moment price makes a clearly lower high than its own last peak, while price made a higher high. Worth acting on?
CCI oscillates between −40 and +40 for weeks, never approaching either band. A trader keeps looking for a signal anyway. What should they conclude?
Price above, CCI below, watched tick by tick on the left — and the mark it leaves in the ledger on the right. A genuine confirmed divergence, its mirror image — and a false overbought that just kept climbing.
Price makes a new high. Judge whether CCI genuinely disagrees — then call it: a real divergence, or just confirming momentum.
The classic error is trading the raw ±100 crossing as if it were a complete signal. The discipline is mechanical: check the prevailing trend first, then require a genuine divergence between price and CCI before treating it as a warning.
Lambert's statistical measure endures because it's a genuinely clever formula — but no formula replaces reading the trend it's measuring against. Let a genuine divergence, not the crowd's favorite band, do the talking.
In God we trust; all others bring data.