Visa’s latest report, posted in mid-August, reveals another curious numerical quirk. It estimates the number of Level 4 merchants at about 5 million. But in a PCI report for June 2007, Visa estimated the number of Level 4 merchants at about 6.5 million, says Gartner Inc. technology and security analyst Avivah Litan. She interprets that reduction to be a result of PCI causing networks and acquirers to look hard at where their transactions come from and thus make their counting more accurate. “PCI is forcing Visa to get a better handle on who’s connecting to them,” she says.