A wild swing day in the market on Wednesday with a sharp decline in the morning followed by a sharp mid-day rally, then a sharp selloff in the afternoon with a close near the low of the day, setting up for a bearish day on Thursday.
Key support level to watch for on Thursday will be 4500.
-- Selling pressure should intensify below 4500 with the next support at 4480 and then 4440.
-- Ability to stay above 4500 could result in profit-taking rally up to 4550 resistance.
Vietnam devalues dong currency, matching Beijing's yuan move 
