$re = '/[A-Z][A-Z\d, ]*$/m';
$str = '[POS Purchase]
POS Signature Purchase International SKYPE COMMUNICATIO, LUXEMBOURG, LUX
ATM Cash Withdrawal. Surcharge: -3.0 BNEAIR INT DP LSL4 2, BNE AIRPORT, AUS';
preg_match_all($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