Excerpt: Careful use of tax-managed funds can produce up to 9% better long-term returns for retirement than tradition tax-deferred investing, a new study shows. The report by fund giant T. Rowe Price Group Inc.... compared returns of so-called tax-managed strategies to advantages of investing in non-deductible IRA accounts. Researchers analyzed potential gains over 10-, 20- and 30-year rolling periods. In each case, they assumed a 10% annual average return.  MORE >>