With the S&P 500 on pace for a 16% yearly gain already, investors find themselves at a familiar crossroads: lock in profits while they are hot, or stay greedy and bet on a typical year-end rally that could push stocks to new highs.

U.S. stocks closed higher Friday, with shares of Amazon surging following its quarterly earnings results. The Dow, S&P 500 and Nasdaq ended October with monthly gains despite the government shutdown.