Square has become ubiquitous in many cities as an easy and inexpensive way for businesses to process credit card payments. But in Illinois, the company has received a cease and desist order that could endanger their success in that state.
The notice alleges that Square is violating the Illinois' Transmitters of Money Act. The law requires businesses that buy or sell "payment instruments" or transmit money to get a state license.
If Square's plan is to argue the law doesn't apply, their previous actions could make that hard to justify.