Munich Re says profit fell to €3.1 billion ($4.8 billion) last year from €3.2 billion ($5 billion) in 2014 as earnings took a hit from its underperforming Ergo primary insurance unit.

Gross written premium (GWP) grew to €50.4 billion ($78.4 billion) from €48.8 billion ($76 billion), but investment income fell to €7.5 billion ($11.7 billion) from €8 billion ($12.4 billion). The combined operating ratio for reinsurance improved to 89.7% from 92.7%.

For the fourth quarter, GWP climbed to €12.4 billion ($19.3 billion) from €12 billion ($18.7 billion) in the previous corresponding period. Net profit was flat at €700 million ($1.1 billion).

“Due to the fact the market environment is so challenging, the [full-year] result is pleasing,” CFO Jorg Schneider said. “Even though we benefitted from random effects in the form of a low impact from major losses, the good result is mainly due to our operational profitability and rock-solid balance sheet.”

Ergo made a loss of €200 million ($311 million) for the year and €100 million ($155.7 million) in the fourth quarter.

“Changes in the value of derivative financial instruments and negative currency effects, along with goodwill impairments in the Ergo field of business, had an overall adverse impact,” the reinsurer said.

Natural catastrophe losses cost Munich Re €149 million ($232 million) during the year, down sharply from €538 million ($837 million) in 2014.

Heavy flooding in northern Chile was the costliest natural disaster, with a final bill of €47 million ($73 million), while the chemical storage explosions in the Chinese port of Tianjin led to the largest individual loss, at €175 million ($272 million).