FINRA Rule 3270: 

Outside Business Activities of Registered Persons 

No registered person may be an employee, independent contractor, sole proprietor, officer, director or partner of another person, or be compensated, or have the reasonable expectation of compensation, from any other person as a result of any business activity outside the scope of the relationship with his or her member firm, unless he or she has provided prior written notice to the member, in such form as specified by the member. Passive investments and activities subject to the requirements of NASD Rule 3040 shall be exempted from this requirement. 

Supplementary Material: 

.01 Obligations of Member Receiving Notice. Upon receipt of a written notice under Rule 3270, a member shall consider whether the proposed activity will: (1) interfere with or otherwise compromise the registered person's responsibilities to the member and/or the member's customers or (2) be viewed by customers or the public as part of the member's business based upon, among other factors, the nature of the proposed activity and the manner in which it will be offered. Based on the member's review of such factors, the member must evaluate the advisability of imposing specific conditions or limitations on a registered person's outside business activity, including where circumstances warrant, prohibiting the activity. A member also must evaluate the proposed activity to determine whether the activity properly is characterized as an outside business activity or whether it should be treated as an outside securities activity subject to the requirements of NASD Rule 3040. A member must keep a record of its compliance with these obligations with respect to each written notice received and must preserve this record for the period of time and accessibility specified in SEA Rule 17a-4(e)(1)