Stock index futures held to losses on Wednesday after a report showed the U.S. private sector shed slightly more jobs than forecast in December.

S&P 500 futures fell 3.4 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 dropped 34 points and Nasdaq 100 futures lost 4 points.

The ADP Employer Services report showed U.S. private employers shed 84,000 jobs in December, down from a revised 145,000 in November but more than the 73,000 forecast by a Reuters survey.

The November figure was originally reported as 169,000.

(Reporting by Rodrigo Campos; Editing by Padraic Cassidy)