The biggest bull on Wall Street last year just became the most bearish strategist of 2017

Tom Lee
Katie Kramer | CNBC

Tom Lee, the most bullish strategist at one point in 2017, just became the most bearish soothsayer on Wall Street.

In a note to clients Friday, Lee issued a 12-month price target of 2,275 for the , the lowest forecast among Wall Street strategists tracked by CNBC. The new price target implies a gain of 0.3 percent from Thursday's close.

Lee, who is head of research at Fundstrat Global Advisors, an independent research boutique firm he founded two years ago after a long career at JPMorgan, says there are many risks in 2017.

Among those risks, the strategist believes President-elect Donald Trump may have a difficult time passing his pro-growth policies, an outcome that could lead to investors' disappointment and a potential market reversal.