Last week I discussed why costs matter when investing. By considering taxes as an additional expense, you'll be able to make informed decisions that, all else being equal, can help your portfolio's returns over the long run. Research by Vanguard's Investment Counseling & Research group shows that taxes on dividends and capital gains can be a significant drag on a fund's overall performance—in many cases, the largest single drag. And that's particularly true for stock funds. (more…)