Prop. Treas. Reg. No. 109369-10 (Nov. 25, 2011)

(defines "interest in a limited partnership as a limited partner" for material participation test under the passive loss rules of I.R.C. Sec. 469; in defining interest, key is whether taxpayer has a right to participate in management at any time during tax year rather than whether the taxpayer has limited liability, and whether entity classified as partnership for federal income tax purposes).