Uber and Lyft drivers in San Francisco will have to register for a business permit if they want to continue earning money from giving and sharing rides. City Treasurer Jose Cisneros has begun sending out letters to 37,018 drivers in the city letting them know of the new requirement, according to SFGate. It's unclear how Cisneros got a hold of their names and why he's suddenly decided to enforce a new rule. But SFGate notes that the city is basically telling the companies that if they refuse to recognize their drivers as employees, then they have to require them to get business permits as contractors. Also, if every driver applies for one, which costs $91 a year for those who make $100,000 or less in gross receipts, then the city will make $3.37 million a year.