US STOCKS-Wall St cuts gains, Nasdaq off as oil offsets ADP jobs

* Oil rises sharply, driving the Nasdaq lower

* ADP shows employers unexpectedly added jobs in July

* Financials supported by Fed, SEC measures

* Dow up 0.6 pct and S&P up 0.5; Nasdaq falls 0.5 pct (Updates to midday)

By Walter Brandimarte

NEW YORK, July 30 (Reuters) - U.S. stocks cut gains while the Nasdaq slipped into negative territory on Wednesday as oil prices rose sharply, offsetting positive jobs data and efforts by U.S. officials to boost liquidity in turbulent financial markets.

Bank shares trimmed some of their earlier gains and energy companies' stocks rose as U.S. crude oil prices jumped more than $2 per barrel, after falling for most of the morning and closing sharply lower on Tuesday.

The spike in oil prices took some of the shine off an ADP Employer Services' report that showed that U.S. private-sector employers added 9,000 jobs in July, suprising economists who had expected a fall in that number.

The report encouraged investors to bet the government's more comprehensive labor market report due on Friday will paint a brighter picture for the U.S. economy -- supporting shares of consumer products companies such as General Electric Co (GE.N: Quote, Profile, Research) and Procter & Gamble Co (PG.N: Quote, Profile, Research).