$re = '/([a-z\.]+):\d/mi';
$str = '9 40 0.5752 2 0.0000 *BRK.B:23.42:24.08:-2.82% PFE:28.05:26.94:3.97%
9 40 0.5752 2 0.0000 *NOV:23.42:24.08:-2.82%
3 50 0.5752 7 0.0000 C:23.42:24.08:-2.82% *AAPL:28.05:26.94:3.97%% *MMM:28.05:26.94:3.97%';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php