No, there is no law obligating creditors, whether "private parties" or large, publically traded companies, to notify credit rating bureaus of your payments or defaults. A creditor may refrain from notifying the bureaus or agencies about your transactions, but if it has notified them, but it needs to provide complete and accurate information--it may not report partially, incomplete, or innaccurate information about your credit. So it can refrain from reporting entirely, but once it does report, must do so correctly.