$re = '/\b(?:Bs|Usd)\s+(?:\d{1,3}(?:,\d{3})*(?:\.\d+)?|\d{4,})(?=\s+Cuenta\b|$)/m';
$str = 'Cuenta de Ahorros | 1231231231 Bs 1023,423.88 Cuenta de Ahorros | 1231233123 Usd 102,423.88 Cuenta de Ahorros | 87316633 Usd 10.233 Cuenta de Ahorros | 49189387113313 Usd 12.301';
preg_match_all($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