Principal Funds has been named one of the hottest fund firms of the year by InvestmentNews, a weekly newspaper for financial advisers. The rating is based on net inflows to mutual funds through Oct. 31, 2012, as tracked by Morningstar. Principal Funds came in at No. 9 of 10 funds, with $7.8 billion in year-to-date net inflows. Vanguard Funds was the top fund firm on the list, with $81 billion year-to-date in net inflows.