AP4, Stockholm, recorded a net return of 13% for the six months ended June 30, with assets increasing to 391.4 billion Swedish kronor ($42.1 billion).
In an update Friday, the pension fund said the return equated to a gain of 45.2 billion kronor. For the six months ended June 30, 2018, the pension fund returned 3.9%. Comparative figures for the six months ended Dec. 31 were not available.
Assets increased 12% from Dec. 31 and increased 6.7% from June 30, 2018.
AP4 achieved a five-year annualized net return of 9.3%, and 10.4% for 10 years.
The pension fund's 40% global equities allocation returned 14.5% for the six months ended June 30, while Swedish equities, which made up 15.7% of the allocation, returned -26.3%.
On the fixed-income side, the 21% global interest rates allocation gained 4% for the six-month period, and the 11.6% allocation to Swedish interest rates also gained 2.5%. Real assets achieved a 7.1%, with a 11.6% allocation. Other assets, with a 0.1% allocation, returned 0.1%.
"The return during the first half of 2019 was the highest return that AP4 has had for a single first half-year since the start of the new pension system in 2001," CEO Niklas Ekvall said in a news release. "This is of course very gratifying. But it illustrates perhaps above all the volatile market environment that we currently find ourselves in, and the fact that evaluation of a pension fund must be done over a long period of time in order to be meaningful."