MUNICH (Reuters)—Munich Reinsurance Co. posted a smaller-than-expected net loss in the first quarter as its tax bill fell in the wake of devastating earthquakes in Japan and New Zealand.

The world's biggest reinsurer had already primed the market to expect a "clearly negative" quarterly result, after penciling in €2.7 billion ($3.9 billion) for natural catastrophe insurance claims from disasters including the two earthquakes as well as flooding and a cyclone in Australia.

"Despite these devastating natural catastrophes, we can still achieve a profit for the year as a whole," Chief Financial Officer Joerg Schneider said in a statement on Monday, reiterating its latest outlook.

Munich Re had ditched its full-year target of earning about €2.4 billion ($3.4 billion) in net profit in the wake of the disasters.

"Thanks to our broad spectrum of activities, with life reinsurance, primary insurance and Munich Health, we will be able to partly counterbalance the catastrophic losses in property-casualty reinsurance," Mr. Schneider said.

The quarterly net loss was €947 million euros ($1.4 billion), after minorities, which was smaller than the €1.06 billion ($1.5 billion) average of 10 estimates in a Reuters poll of banks and brokerages.

The result was favored by a tax gain of 612 million ($878 million) in the quarter resulting from the quarterly loss. Group gross premiums also rose 11.3% to nearly €13 billion ($18.7 billion).

Munich Re's operating loss of €1.35 billion ($1.94 billion) was wider than the average loss of €1.2 billion ($1.7 billion) in the poll.

"Munich Re reported broadly in line with consensus and ahead of our forecast on the back of a more favorable tax rate," said Silvia Quandt Research analyst Christian Muschick.

"Given a below consensus forecast operating result we believe that the figures will not cause a lot of applause in the market," Mr. Muschick said.

Munich Re shares, seen down 0.5% ahead of the market open, have fallen by nearly 9% since Feb. 21, the day before a 6.3 magnitude earthquake struck Christchurch, New Zealand. It fell by 4% in the wake of the magnitude 9.0 earthquake and tsunami in Japan.

Data from StarMine, which weights analysts' forecasts according to their track record, show Munich Re trading at 12.8 times 12-month forward earnings, a discount to rival Swiss Reinsurance Co. at a multiple of 14.8 but a premium to Hannover Re Group, which trades at a multiple of 8.4.