Square uses "Gross Payment Volume" to describe that, not revenue. GPV is ~$30 billion.
You can search for GPV in the S-1 to see the specifics: https://www.sec.gov/Archives/edgar/data/1512673/000119312515...
You can search for GPV in the S-1 to see the specifics: https://www.sec.gov/Archives/edgar/data/1512673/000119312515...