as did 3m, caterpillar, at&t, american express, microsoft, all dow components, by the way. meanwhile, federal reserve chairman ben bernanke spooked the marks with the semiannual testimony before the senate banking committee. bernanke said we are seeing, quote, an unusually uncertain economy. he did say though, that he did expect a moderate economy. about bernanke said the federal reserve was prepared to take steps, any steps needed, if the economy did take another leg down. he did not say what those steps would be. chairman bernanke may be concerned about an unusually uncertain economic outlook, but nigh next guest says he feels like the last optimist standing. he isser is me segal, professor of finance at the wharton school and uthor of "stocks for the long run." always great to have you on the program. welcome back. >> thank you very much, maria. >> so the markets have been so mixed these last few weeks, but you think it's a great time for investors. what makes youo so optimistic? >> they're allowed shrm uncertainties, but i look at valuation. i look at earnings and i loo