N.Y. Limited Liability Company Law § 1304
No foreign professional service limited liability company shall engage in any profession or carry on, or conduct or transact any other business or activities in this state other than the rendering of the professional services or the carrying on, or conducting or transacting of any other business or activities for which it is formed and is authorized to do business in this state; provided that such limited liability company may invest its funds in real estate, mortgages, stocks, bonds or any other type of investments; provided, further, that a foreign professional service limited liability company (i) authorized to practice law may only engage in another profession or other business or activities in this state or (ii) which is engaged in a profession or other business or activities other than law, may only engage in the practice of law in this state, to the extent not prohibited by any other law of this state or any rule adopted by the appropriate appellate division of the supreme court or the court of appeals.
N.Y. Limited Liability Company Law Law § 1304