US stocks, which have been choppy so far this week, started trading Wednesday flat on weak data, although the focus remains firmly fixed on the US central bank chief’s speech in Wyoming this week. New data showed mortgage applications fell again last week, dropping to a 22-year low due to rising borrowing costs, while orders for big-ticket manufactured goods were flat. But amid the Federal Reserve’s aggressive campaign to cool the highest inflation in four decades with steep interest rate hikes, Fed Chair Jerome Powell’s speech on Friday in Jackson Hole is the week’s main event. Investors are poised for more hawkish commentary — but hoping for signs that policymakers might be ready to pull back soon. Briefing.com analyst Patrick J O’Hare said there is a “mountain of expectations building” for the speech, which Powell is due to deliver at the annual central banking symposium. “Those expectations range from fear of a resolutely hawkish speech to hope of a tempered rate-hike outlook,” he said.