A jolt for banking investors, as Westpac flagged a 20-percent drop in Q3 mortgage applications, blaming the combined effects of three interest rate rises this year, and Federal Budget tax changes. Westpac shares slid nearly 6 per cent. David Scutt of StoneX Group tells Rena Sarumpaet, that should CBA offer similar disappointment in Wednesday's annual result, the best days of the month long banking rally may be past.