UPDATE-2-Munich Re Q3 premiums up, net misses expectations

* Q3 net 644 mln eur after minorities vs 700 mln poll avg

* Q3 operating profit more than triples to 1.21 bln

* Q3 gross written premiums 10.355 bln, up 11.7 pct

* Share down 2.1 pct, lags index

(Adds detail, analyst comment, background)

FRANKFURT, Nov 5 (Reuters) - Munich Re (MUVGn.DE), the world's largest reinsurer, swung to a net profit in the third quarter from a small year-earlier loss, helped by low natural catastrophe claims and stronger investments.

Still, the quarterly net profit of 644 million euros ($950 million) was below the average expectation for 700 million euros in a Reuters poll, despite a nearly 12 percent rise in booked premiums in the period. [ID:nL2210718]

The company was optimistic about the remainder of the year.

"Munich Re expects a group profit of between 2.2 billion and 2.5 billion euros for 2009 -- at least 700 million more than in 2008," it said in a statement.