Briefly

Principal Financial Group, a life insurer specializing in retirement savings plans, said Iowa regulators approved its conversion to a stock company. The Des Moines-based company is planning a $2.1-billion initial public offering this year. . . .

Pop star Michael Jackson is set to continue his tour of U.S. stock markets by presiding over the opening of Nasdaq trading Thursday, the No. 2 U.S. market said. Jackson, who is in New York for a concert honoring his 30 years as a solo performer, visited the NYSE for a private tour of the Big Board’s trading floor in January.