European stocks trudged higher Wednesday, but gains were small after a run of six straight wins for the region's equity benchmark.

The Stoxx Europe 600 index picked up 0.1% to 336.73, a mild rise after strong advances for regional stocks in the previous session that were supported by upbeat manufacturing readings from the euro zone and the U.S. The index on Tuesday closed up 0.6%.

Among the sharpest decliners on Wednesday were shares of Deutsche Boerse AG , down 2.4% as the German exchange operator said its Clearstream Banking unit is subject to a criminal investigation in the U.S. related to alleged violations of money laundering and Iran sanction laws.

France's CAC 40 was down 0.2% at 6,640.53, pulling back after logging its highest closing level since September 2008. Pressure came in part from ArcelorMittal . The steelmaker's shares dragged 1.5% lower after a ratings downgrade to neutral from outperform at Credit Suisse, "based on lack of earnings momentum, cycle risk and valuation."

The U.K.'s FTSE 100 swung between small gains and losses, recently picking up 0.1% at 6,661.67. Germany's DAX 30 index rose 0.2% to 9,641.33, aided by a 3.6% gain in shares of Deutsche Post AG following a projection of earnings growth from the logistics and mail company.