There are more than 15 billion stolen account credentials being sold or even shared for free on the dark web, with individual entries selling for an average of $15.43, a new research report states. Roughly one-third of the credentials, or about 5 billion, are unique, according to Digital Shadows, whose researchers reached these totals following an analysis of two-and-a-half years of advertised account credentials found across nine active and defunct dark web marketplaces.