A little over 21 million login credentials stolen from Fortune 500 companies have been found in various places on the dark web. The information was compiled by crawling multiple resources, like markets in the Tor network, web forums, Pastebin, IRC channels, social networks, and messenger chats. 95% of the credentials contained unencrypted, or brute-forced and cracked by the attackers, plaintext passwords. Most industries in the top ten with the weakest passwords have a third or more logins that could be cracked in seconds.
Source: https://www.bleepingcomputer.com/news/security/21-million-logins-for-top-500-firms-offered-on-the-dark-web/