Stocks continued to slide lower, but are off session lows. Wall Street is following Europe's lead. Global equity markets are down on fears of instability of Portugal's banking industry. But Scott Wren, Senior Equity Strategist at Wells Fargo Advisors (WFC) remains unconcerned. Wren said, "fundamentals and valuations are goodÂ¦ valuations are certainly not stretched." He also said, "In our opinion, pullbacks equal opportunity." And some investors may be seizing that opportunity with airline stocks. United Continental Holding (UAL) is getting a lift. Shares are up more than 7 percent after reporting positive news on its revenue per available seat mile. TheStreet's Susannah Lee reports from Wall Street.