How does Wells Fargo use my phone number to find my Bank of America account?

I’m extremely confused about how Wells Fargo’s SurePay transfers money to Bank of America.

I’ve set up my Bank of America account to use my mobile phone number to receive payments.
Now someone sent me money via Wells Fargo’s SurePay money transfer service, using my mobile phone number as the recipient.
I witnessed that the sender never specified my account number or other account information. In fact, the sender never even specified that the receiving bank is Bank of America.
The only information entered was my first name, last name, and phone number.

Next thing I know, I receive a text on my phone from Bank of America saying that my account will be credited with the transferred money (and I confirmed this online on BoA’s website).

While this is convenient, I’m extremely confused and a little creeped out at how this was done:
How did Wells Fargo know that my phone number was associated with Bank of America?!
Is there some kind of global database that maps phone numbers to accounts across banks?
What if my phone number was associated with multiple accounts and/or multiple banks? etc.