* STOXX 600 index drops 0.3 pct
* M&A talk boosts RWE, Innogy shares
* Banks, energy sectors weigh
* Dutch election, U.S. rate decision in focus (Adds details, closing prices)
By Kit Rees
LONDON, March 14 (Reuters) - After four days of gains, the pan-European STOXX 600 index dropped 0.3 percent on Tuesday, weighed down by bank and energy stocks, as well as uncertainty over elections in the Netherlands and a U.S. interest rate decision.
The biggest fallers among the banks were Bank of Ireland and Italy's Banco BPM and BPER Banca , which were between 2.6 and 3.3 percent lower.
Meanwhile the prospect of a new Scottish independence referendum led to falls in Royal Bank of Scotland and Lloyds of 2.5 percent and 1 percent respectively, analysts said.
Markets were largely focussed on the Netherlands' parliamentary election on Wednesday as well as the U.S. Federal Reserve's interest rate decision.
"Investors could be seen to be taking some risk off the table with several potentially volatile events lined up," Charles Hanover Investments partner, Dafydd Davies, said.
Deal-making speculation was the main driver behind stock moves, with German utility RWE the biggest STOXX gainer, jumping 6.5 percent after saying it might cut its stake in networks and renewables unit Innogy to 51 percent.
RWE, which also forecast a higher profit in 2017, did not comment on a Bloomberg report that France's Engie was considering a bid for the company.
Innogy shares rose 4.3 percent, but pared some of their earlier gains after French BFM TV reported that Engie was not interested in making a bid.
Fiat Chrysler rose as much as 2.6 percent after Volkswagen CEO Matthias Mueller said he did not rule out possible merger talks with its Italian-American peer. Fiat pared the gains to end down 0.3 percent.
Shares in Swiss drugmaker Galenica fell 5.1 percent after the firm posted a drop in 2016 profit, saying that the acquisition of U.S.-based Relypsa last year had a negative impact on the group's results.
Britain's FTSE 100 fell 0.1 percent on political uncertainty as Britain prepares to start negotiating its departure from the European Union. (Additional reporting by Danilo Masoni; Editing by Louise Ireland and Alexander Smith)