European stocks closed with small gains Wednesday, helping the region's benchmark to a fresh 21-month high. The Stoxx Europe 600 index SXXP, +0.16% edged up 0.2% to finish at 396.45, its highest closing level since August 2015. That comes after the pan-European gauge tacked on 0.5% on Tuesday. The index is up 9.7% this year, after getting a boost ahead of markets-friendly Emmanuel Macron's victory in the French presidential election on Sunday.

The Dow Jones Industrial Average was trading in negative territory late Wednesday afternoon, weighed down by a late-afternoon slump in shares of Boeing Co., Walt Disney Co., and 3M Co. The trio of Dow DJIA, -0.16% components combined were cutting about 45 points from the blue-chip gauge, which was off 50 points, or 0.2% at 20,924.

Stocks in Asia were broadly higher Wednesday, as local drivers outpaced global geopolitical concerns, though shares in South Korea reversed early gains on investor caution following the presidential elections. Markets had a muted reaction to the unexpected firing of James Comey, the director of the Federal Bureau of Investigation.