Operating earnings declined by 3% to $213m for first quarter 2012, against $219.8m during the corresponding quarter of 2011 while operating revenues were $2.1bn against $2.bn for the same period last year.

Principal Global Investors chairman, president and chief executive officer Larry Zimpleman said that the company had strong investment performance and impressive sales and net cash flows across full service accumulation, principal funds, principal international and principal global investors.

"We continue to invest in our businesses, both organically and through strategic acquisitions, in order to grow in the right markets that position us for the long term," Zimpleman said.

For the current quarter its retirement and investor services segment operating earnings stood at $143.6m compared to $154.1m during the same period last year.

Principal global investors segment registered operating earnings of $16.2m versus $16.6m in the prior year quarter, mainly due to higher compensation costs as the firm increased distribution and investment staff to support growth.

Operating earnings of the international segment were $41.8m during the current quarter of 2012, compared to $27.8m in the prior year quarter, backed by increase in assets under management.