Some traders consider it a buy signal if a security’s RSI reading moves below 30. This is based on the idea that the security has been oversold and is therefore poised for a rebound. However, the reliability of this signal will depend in part on the overall context. If the security is caught in a significant downtrend, then it might continue trading at an oversold level for quite some time. Traders in that situation might delay buying until they see other technical indicators confirm their buy signal.