of a regular business. 15 U.S.C.  78c(a)(4) and (5) (1999). Persons are required to be registered with the SEC or with a state securities regulator, as appropriate, as investment advisers if they are engaged in the business of advising others about securities for compensation. 15 U.S.C.  80b-2(a)(11) (1999). 91 SEC Rule 15c3-1 requires a broker-dealer to maintain at all times its minimum net capital requirement prescribed under the Rule. Under SEC Rule 15c3-1, if a broker-dealer's net capital falls below its prescribed minimum requirement under the Rule, it must cease conducting a securities business.