I received the same letter. Here is the info from the SDAR site:
Issue: Business License Tax
Position: The San Diego Association of REALTORSÂ® is opposed to the requirement of a business license tax for any real estate licensee affiliated with a Real Estate Brokerage.
Statement: SDAR supports the position that licensees should not be required to individually pay a business license tax since they are required to be under the supervision of a broker in a stated place of business, the same conditions as other commercial businesses with employees. The California Business and Professions Code is clear as to nexus between a broker and those licenses maintained at his/her office. It requires that a broker shall be responsible for the supervision and control of activities conducted by employees/ licensees. The IRS classifies salespersons as independent contractors. Each associate licensee who is affiliated with an office under the supervision of a broker or corporation must comply with the terms of an Independent Contractor Agreement at a stated place of business.