HSBC (LON: HSBA) shares have big potential this Friday, according to Central Markets' Joe Neighbour. He says they've recently completed a triple bottom formation on the breakthrough resistance at 635p. The subsequent pullback to test the support has held nicely which has led to the creation of a bull flag.  This bullish continuation pattern completed last week and the shares look set to move higher. The relative ratio also looks bullish and supports this buy recommendation.