Why it matters
Many web hosts and website builders are resellers. Your account lives with them, but the registrar behind them is the party that talks to the registry. This matters during a sale. A reseller may add steps to an outbound transfer, or may not give you an auth code at once. Check who the real registrar is in the registration data before you promise a delivery date. Sellers should also keep their account login active. A common mistake is letting a reseller account lapse and then losing access to a valuable name.
Source: sullysblog.com
Read nextHow Domain Transfers Work: Auth Codes, Transfer Locks, and Push vs Transfer