Valuation of partner's profit-sharing right prescribed; income-based multistep method and proportionate application determine taxable value. CBOT prescribes a three-step income-based method for valuing a partner's right to share profits without asset entitlement: compute average annual income using assessed income or books with required adjustments, add back partner salaries and interest while allowing reasonable remuneration and a capital-related deduction, exclude non-recurring and capital items; scale the averaged income by a firm-type multiplier; and apply the partner's profit share proportion to the scaled figure to determine the partner's interest value.