UPDATE 3-Danske Q3 profits fall, loan writedowns to stay high

* Q3 pretax profit falls to 1.1 bln DKK, beating forecast

* Bank says sees loan impairments staying high in Q4

* Says sees activity level in Q4 unchanged from Q3

* Shares end down 3.7 percent

(Adds details, quotes; updates share price)

By Peter Levring and John Acher

COPENHAGEN, Nov 3 (Reuters) - Denmark's biggest financial group, Danske Bank (DANSKE.CO) said loan impairment charges were likely to stay high for some time after reporting a smaller-than-forecast drop in earnings for the third quarter.

Earnings were helped by higher-than-expected trading income and slightly lower operating costs than forecast but were burdened by heavier-than-forecast loan impairment charges, which contributed to knocking the bank's shares.

Pretax profits fell to 1.1 billion Danish crowns ($218 million) in July-September from 1.58 billion in the same quarter last year.