What pieces of information are required by law to be reported on the credit report by the the credit grantors?

Nothing. There is no federal or state law which requires or compels credit reporting. It is a totally voluntary activity. The Fair Credit Reporting Act dictates that IF information IS reported, it must be correct. The usual and ordinary information that gets reported voluntarily is name of creditor, some type of account #, date opened, date last updated/reported to the bureau, high credit limit (most highest amount of credit used) or original amount of the loan, balance as of the date last reported, terms (which may or may not be your exact payment amount), the rating and 30-60-90 day counters which give an overview if the account has been paid on time. Other information may include the actual late dates, and other notations/statements like "account closed" or "charged off". You can print yourself a copy of the FCRA by following links at www.ftc.gov