Allianz, based in the Minneapolis suburb of Golden Valley, said Friday it plans to appeal the ruling, which did not address the validity of the allegations that it used deceptive sales and marketing tactics to sell annuities to senior citizens.

"Allianz Life has and will continue to mount a vigorous defense, and we are confident that we will prevail," company spokesman Jim McManus said.

But U.S. District Judge Ann Montgomery's decision Friday in Minneapolis could affect as many as 400,000 people nationwide and expose the company to hundreds of millions of dollars in damages if it were to lose the case, the Star Tribune reported Saturday.

"There is a lot of money involved," said Karl Cambronne, a partner in the Minneapolis law firm that brought the suit.

The Minnesota case is the largest of four class-action suits charging Allianz used deceptive tactics to sell unsuitable annuities to seniors.

Experts contend the elderly should not buy deferred annuities because they tie up money -- sometimes long past life expectancy -- and also are difficult for heirs and beneficiaries to access.