* STOXX 600 up 0.1 pct
* Banco BPM rise on talk of bad loans sale
* But Deutsche Bank drops after U.S. request
* Fiat falls on emission bill worries
* Dixons, Britvic rise after results (Adds details, closing prices)
By Kit Rees
LONDON, May 24 (Reuters) - European shares, stuck just below 21-month highs for more than a week, struggled to gain momentum on Wednesday, with strength in banks and big oil majors offset by weakness in miners and autos.
The pan-European STOXX 600 index ended up 0.1 percent. Among the national markets, Britain's FTSE 100 rose 0.4 percent, while Germany's DAX fell 0.1 percent, weighed down by stocks including Hugo Boss and Evonik going ex-dividend.
Banks were the biggest contributor to gains on the STOXX index with Banco BPM leading the way with a surge of 4 percent, helped by market talk about the sale of bad loans.
But the sector was weighed down by a 0.9 percent fall in Deutsche Bank after news that U.S. House Democrats had asked the German lender to provide information on whether any accounts connected to U.S. President Donald Trump have ties to Russia.
European auto stocks were the biggest sectoral fallers, down 0.6 percent. They were led lower by a 1.6 percent fall in Daimler, which extended losses after its sites were searched on Tuesday by German prosecutors in an emissions probe, and a 0.6 percent fall in Fiat Chrysler .
Shares in the Italian-American carmaker recouped some of their earlier losses after the U.S. government sued it over emissions.
"This case is likely to take a long time (VW settled in 16 months) and should weigh on FCA’s share price for some time as the message regarding the execution of its 2018 plan is likely to be overwhelmed," analysts at Barclays said in a note.
Among mining stocks, hit by a fall in copper after Moody's downgraded China, a big global metals consumer, Rio Tinto declined 0.5 percent while Randgold and Fresnillo fell 1.5 and 0.4 percent respectively.
Glencore lost 0.1 percent after saying it had made an informal approach to U.S. grains trader Bunge to discuss "a possible consensual business combination". But Bunge responded by saying it was not in talks with the mining and commodities group.
On the positive side, a well-received set of fourth-quarter results from Dixons Carphone lifted its shares 4.7 percent, while Britvic's first-half update also boosted its shares.
British retailer Kingfisher was the biggest STOXX faller, however, down 7 percent after a trading update, while engineer Babcock also fell 2.3 percent after its full-year results.
Additional reporting by Danilo Masoni; Editing by Vikram Subhedar and Kevin Liffey