Why is my Apple Pay asking for my social security number?

Apple Pay does not ask for an SSN at all. Apple Cash may ask for an SSN for identification in certain cases. That's a Green Dot bank requirement.

click here ➜ Identity verification for Apple Card or Apple Cash - Apple Support

Why you'll be asked for your personal data

Apple Cash services are provided by Green Dot Bank,

Member FDIC, a regulated financial institution. Green Dot Bank is

required by federal law to verify the identity of its customers.

To verify your identity, Green Dot Bank will request Social Security

numbers and other personal information to ensure that customers are

eligible to use the service.

Apple Pay is not asking for your SSN. Is it Apple Cash? Apple is not a bank. Apple Cash is a service of Green Dot Bank. Green Dot Bank is governed by both federal and state banking regulations and audited frequently for compliance by federal regulators.

The Patriot Act, enacted after 9/11 requires that lenders, banks etc obtain a confirmed ID. This regulation and others are known as Know Your Customer (KYC) laws.

“To help the government fight the funding of terrorism and money laundering activities, Federal law requires all financial institutions to obtain, verify, and record information that identifies each person who opens an account. What this means for you: When you open an account, we will ask for your name, address, date of birth, and other information that will allow us to identify you. We may also ask to see your driver's license or other identifying documents.”