The historically strong period might not pan out this time around. : CHAPEL HILL, N.C. (MarketWatch) — The stock market in the third year of Donald Trump’s presidency may turn out to be a big disappointment. That would come as a shock to many bulls, who have been counting on stocks in the next 12 months of living up to their historical tendency to perform well in the third year of the presidential term. Since many researchers define the presidential terms in fiscal years ending Sept. 30, that means we have just entered this favorable third-year time frame.