The sell down of OCBC today is likely due to the Citi's downgrade from Neutral to Sell, setting a TP of SGD27.5. This is actually a prediction of where the stock could trade down to if their concerns of slowing growth ("flat Q3 earnings"), shrinking profit margins from net interest income play out. Sometimes, such are "sell the rumour" event before a catalyst - do note that this is a prediction and not a fact (which is to be proven with the actual result).