European shares closed marginally higher on Wednesday, after a bumpy day of trading, as investors looked ahead to the much-anticipated U.S. Federal Reserve's policy statement.
The pan-European FTSEurofirst 300 provisionally closed 0.1 percent higher, at 1,318.51 points.
London's FTSE ended around 0.7 percent higher and Germany's DAX closed approximately 0.1 percent higher.
But some major stock markets ended the day in the red, with the Spanish benchmark IBEX down around 1.4 percent and Italy's MIB some 1.6 percent lower. Fears about the region's banking sector following the results of Europe-wide stress tests weighed on these countries, with Italian bank stocks particularly badly hit on Wednesday.
Shares in Banca Monte dei Paschi di Siena were suspended when they hit a lower limit earlier in the day. The bank fared badly in the stress tests, and was identified as having the largest shortfall in capital when the results were published on Sunday.
Read MoreUK in a corner over EU budget bill
European markets
Investor await Fed
In the U.S. stocks drifted on Wednesday as Wall Street awaited a monetary-policy decision from the Federal Reserve. The central bank's policy committee concludes a two-day session on Wednesday, where it is widely expected to announce the end of its massive bond-buying stimulus.
Read MoreMarkets could shrug off Fed if it sounds dovish
A new CNBC survey revealed that market participants had scaled back their expectation of an interest rate hike. A rate hike is now seen in July 2015, a month later than participants' forecast in September.
Sanofi CEO ousted
In other stock news, Sanofi shares continued to slide on Wednesday after new chief executive Chris Viehbacher was ousted by the board, with chairman Serge Weinberg to take the helm until a successor is found. Shares fell as much as 6 percent before closing around 4.5 percent lower.
It comes after the French pharmaceuticals group plunged around 10 percent on Tuesday when it said sales of its diabetes treatments would remain flat next year, sparking investor fears about the firm's biggest business.
Read MoreSanofi ousts CEO after warning on diabetes business
At the other end of benchmarks, Frankfurt-listed shares of Fiat Chrysler jumped over 18 percent after it announced plans to spin off Ferrari. Stock in the carmaker ended the day around 12.79 percent higher.
Total warned on Wednesday that sliding oil prices had hit its third-quarter results and could weigh for the rest of the year, following the shock death last week of chief executive Christophe de Margerie. The oil and gas supermajor posted a 2 percent fall in quarterly net profit to $3.6 billion versus the same period in 2013, but this was better than forecast and shares closed around 1.9 percent higher.
Read MoreWeak oil price hits Total results
Shares of Air France-KLM slipped to close 0.8 percent lower after it said it would limit investments and accelerate cost controls next year to mop up the hit from the recent pilot's strike. Its operating profit fell by more than half in the third quarter.
Deutsche Bank fell over 2.38 percent after reporting a net loss in the third quarter as heavy legal costs weighed on earnings. A modest rise in investment banking results lagged many of the big gains seen by its peers.