$re = '/\"orderEnteredBy\":\"(?<orderEnteredBy>[^\"]*)\"/m';
$str = 'availableBalance":{},"projectedBalance":{}}},"productSummary":{"symbol":"RPACX","displayValue":"RPACX","cusip":"32254T759","assetType":"MUTUAL_FUND","description":"UFACRESCENT FUND N/L","settlementDuration":4,"omnibusProduct":true},"orderEnteredBy":"JANEDOE","orderUpdatedBy":"SYS_USER","dirtyFSTT":false,"messagesSummary":{"messagesCount":2,"errorsCount":0,"warningsCount":0,"infosCount":0},"assetType":"MUTUAL_FUND","fundServTransactionTypeDetails":{"cdscValueOverridable":false,"netAssetValue":"NAV_OTHER","rightsOfAccumulation":{"additionalHoldings":0,"manualOverride":false,"additionalHoldingsValid":true}';
preg_match_all($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