"Eventually you're going to run out of rich people, right? And you've got to start targeting middle-class people, upper-middle class people," Nixon says. "I know people that have been SIM-swapped that have no clear indication as to why, aside from the fact that they get paid and they have a retirement account."
-- Martin Kaste, NPR
Our identities (generally) boil-down to just three things; our Social Security Number, our birthday and our phone number. One easy method of protecting a phone number (over and above assigning a PIN number to the account) is to use a Google Voice number for non-critical registrations, like social media.