Under Article 280, the Finance Commission is required to make recommendations on which of the following matters?

Article 280(3) specifies three categories of duties for the Finance Commission: (a) the distribution between the Union and the States of the net proceeds of taxes to be divided and the allocation among the States of their respective shares; (b) the principles which should govern the grants-in-aid of the revenues of the States out of the Consolidated Fund of India; and (c) any other matter referred to the Commission by the President in the interests of sound finance. Thus, it is not limited to tax distribution alone but includes a residuary referral power vested in the President, making the Commission's mandate broad and flexible.