The loss was equivalent to 1.68 trillion kroner.
The fund had a value of 11.66 trillion Norwegian kroner ($1.18 trillion) as of June 30. The market value fell 682 billion kroner in the first half of 2022.
CEO Nicolai Tangen said in the release that the market in the first six months of the year "was characterized by rising interest rates, high inflation, and war in Europe."
All sectors saw negative returns except energy, which gained 13%. The energy returns were due to sharp price increases for oil, gas and refined products, Mr. Tangen said.
"Equity investments are down with as much as 17%. Technology stocks have done particularly poorly with a return of -28%," Mr. Tangen said.
The fund invests in international securities in foreign currency, so returns are measured primarily in international currency — a weighted combination of the currencies in the fund's benchmark indexes for equities and bonds. "A weaker krone cushioned the fall in the fund's market value in krone terms," the report said.
Equities make up 68.5% of the fund, fixed income 28.3%, unlisted real estate 3% and unlisted renewable energy infrastructure 0.1%.
Equities returned -17%, fixed income returned -9.3%, unlisted real estate returned 7.1% and unlisted renewable energy infrastructure returned -13.3%, NBIM reported.
A call to NBIM for further information was not immediately returned.