Tex. Tax Code § 171.1055
(c) In apportioning margin, receipts derived from transactions between individual members of a combined group that are excluded under Section 171.1014(c)(3) may not be included in the receipts of the taxable entity from its entire business done as determined under Section 171.105.
Acts 2006, 79th Leg., 3rd C.S., Ch. 1 (H.B. 3), Sec. 5, eff. January 1, 2008.
Acts 2007, 80th Leg., R.S., Ch. 1282 (H.B. 3928), Sec. 21, eff. January 1, 2008.