they may not be the same "company" but they are owned by the same person or "holding company".
http://www.miaminewtimes.com/issues/...4/feature.html
Here they say that 8thstreetlatinas and oxcash are owned by the same person, and check the fax numbers for
oxcash
http://www.whois.sc/oxcash.com
and nastydollars
http://www.whois.sc/nastydollars.com
you'll see the only difference is the last digit. The numbers are too close for them to be just a coincidence.