Oil fluctuated as German investor confidence jumped to a seven-month high in December and as OPEC members gathered in Vienna to discuss output levels.

Prices swung between gains and losses as confidence in Germany, the biggest oil user in the European Union, increased more than economists forecast on speculation the economy will gather momentum next year. The Organization of Petroleum Exporting Countries will probably leave its production quota unchanged when it meets tomorrow.

The ZEW Center for European Economic Research in Mannheim said its index of investor and analyst expectations, which aims to predict economic developments six months in advance, climbed to 6.9 from minus 15.7 in November. Economists predicted a gain to minus 11.5, according to the median estimates.

OPEC crude output tumbled to the lowest level in 11 months in November as Saudi Arabia, the group’s biggest producer, pumped the least in 13 months, according to revised data in an e-mailed report from the group.

Crude for January delivery rose to $86.37 a barrel on the New York Mercantile Exchange.

Brent for January settlement on the London-based ICE Futures Europe exchange gained 42 cents, or 0.4 percent, to $107.75 a barrel.