$re = '/^\d+/\d+/\d+ .*(?:\n(?!^\d+/\d+/\d+ ).*)*/m';
$str = '05/06/21 05/06/21 Margin Div/Int - Income ACTIVISION BLIZZARD INC
COM
Payable: 05/06/2021
QUALIFIED DIVIDENDS 23.50
ATVI - 0.00 23.50 (9,425.77)
05/13/21 05/13/21 Margin Div/Int - Income APPLE INC
COM
Payable: 05/13/2021
QUALIFIED DIVIDENDS 6.16
AAPL - 0.00 6.16 (9,419.61)
05/28/21 05/28/21 Margin Div/Int - Income STARBUCKS CORP
COM
Payable: 05/28/2021
QUALIFIED DIVIDENDS 18.00
SBUX - 0.00 18.00 (9,401.61)
05/28/21 05/28/21 Margin Div/Int - Expense MARGIN INTEREST CHARGE
Payable: 05/28/2021
- - 0.00 (73.03) (9,474.64)';
preg_match_all($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