PII is more than just the classic SSN, name, and address etc. The IRS uses your last years tax data when verifying your identity for example. Your transaction history is PII as someone can correlate specific transactions to your identity.
It is personal data because it can be correlated to PII. It is not by itself PII. This is one of the most important differences between the US and EU regimes, regulating PII vs. all personal data.
