The 1B number would contain multiple records per person.

For example if I (as a German in Germany, ymmv) open a bank account online that involves a call with one of these companies where they take pictures and information from my passport and check that that's me. Then I choose payment in installments on some online shop, same game. Apply for a small loan? Same game. Set up an account for trading (stock exchange or crypto)? You guessed it, another call. Another payment in installments, backed by the same bank? Apparently verifying my identity again is easier than checking their database. Each of those is another record. Potentially with a new identity document, address or even name (maybe you got married) but mostly just the same data confirmed again with another timestamp

Not all of them use the same identity verification service, but there aren't that many. And I wouldn't be surprised to learn that many are the same company under different brands

Makes sense if the ID verification process involves scanning a driver license or passport.

Edit- rereading this, you’re obviously talking about scale. The original article is much better : https://cybernews.com/security/global-data-leak-exposes-bill...

A record is not necessarily unique. Name changes, address changes, phone number changes, can all create "new" records in dumps like these.