F5 (FFIV) sank 10% late Wednesday after the maker of Web switching gear missed first-quarter earnings targets and guided lower.The Seattle-based company made $22 million, or 53 cents a share, for the quarter ended Dec. 31, up from the year-ago $15 million, or 37 cents a share. Sales rose 7% sequentially and 36% from a year ago to $120 million. Analysts were looking for a 60-cent profit on sales of $118 million. "Including Central and South America, revenue for the Americas grew 13% sequentially, and 39% year over year," said CEO John McAdam. "Growth in Europe was solid while Asia-Pacific revenue was down slightly from the prior quarter. Japan revenue was also down sequentially but was consistent with the seasonal pattern we've seen there during the past three years." The company targets a 44-cent-to-46-cent second-quarter profit on sales of around $125 million. Analysts were looking for a 62-cent profit on sales of $123 million. Shares tumbled $7.84 to $66.64.