Airline stocks fell Wednesday after United Continental's growth plans raised concern it could drive down fares.
Shares of United pulled back 11.4 percent, the biggest decliner in the S&P 500. American Airlines declined 6 percent, while Delta Air Lines fell 5.2 percent and Southwest Airlines dropped 4.7 percent.
United said it expects to increase annual capacity by 4 percent to 6 percent through 2020. This move could squeeze United's profit margins because it could lead other airlines down a similar path, forcing a drop in fares.
"We definitely understand management's decision to focus on improving their domestic network as the company admittedly shrunk too much post the Continental merger, but that was almost a decade ago and investors are likely to be somewhat frustrated by the company's aggressive growth rate," Cowen analyst Helane Becker said in a note Wednesday.
"The stock is unlikely to reflect the company's potential in the near-term as we anticipate competitive actions and investor concerns regarding overcapacity," Becker said.
United also said it expected full-year earnings per share to range $6.50 to $8.50. Analysts polled by StreetAccount expected guidance of $6.99 per share.
—CNBC's Leslie Josephs contributed to this report.
