S&P futures gave up their gains to turn flat on Tuesday after Citigroup Inc reported fourth-quarter results.

Citigroup shed 3.1 percent to $4.97 before the bell.

S&P 500 futures fell 1.1 points and were below fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures added 14 points, and Nasdaq 100 futures fell 17.25 points.

(Reporting by Ryan Vlastelica)