Teresa Isele was appointed acting CEO of AP1, Stockholm, following the dismissal of Johan Magnusson, who violated internal regulations, a spokeswoman said.
Ms. Isele, the fund's general counsel, replaced Mr. Magnusson in the role Monday.
Mr. Magnusson was dismissed by the 352 billion Swedish kronor ($35.8 billion) pension fund's board for breaching policies on the holding and trading of financial instruments, the spokeswoman added. Additional details were not available.
"(Mr.) Magnusson has successfully developed AP1 during his time as CEO, and we on the board are grateful for his efforts. Since it has now emerged that Mr. Magnusson has broken our internal regulations, he unfortunately no longer has the board's confidence. Therefore the board has agreed unanimously that it is not possible for Mr. Magnusson to continue as CEO of AP1," Urban Hansson Brusewitz, chairman of the board, said in a news release.
AP1 will begin recruiting a new CEO immediately, the release said.