It's getting harder and harder to find a pessimistic investor.
Short interest, or bets made by investors that prices will fall, is moving lower. Among S&P 500 stocks on average, short interest declined from more than 4.5 percent of shares available for trading earlier this year to 4 percent as of the end of November, according to Monday report from Bespoke Investment Group.
That 0.5 percentage point decline may seem small to the novice investor, but it is significant. And the decline has been broad: Short interest fell across almost all sectors, the note said.
"If you continue to see this strong push toward the end of the year, you don't see investors feeling the need to short," said Daniel Deming of managing director at KKM Financial.
"It's certainty versus uncertainty in the market, and right now, right or wrong, the market feels fairly certain about some of the decisions it will have to face," he said.