The Oklahoma Bar Journal January 2026

in this fashion, Thielenhaus has, in practical effect, created a unique presumption that all growth of sep arate property is separate property, which in many cases is determi native. This suggests the obvious question: Why does this rule of law exist, given its inconsistency with the remainder of Oklahoma domestic property law? Research into the origins of that rule sug gests it is inconsistent because it is not based on careful judicial con sideration but instead upon a series of unintended alterations. DUBIOUS ORIGINS OF AN UNUSUAL RULE The Thielenhaus opinion cites two cases, Templeton v. Templeton 14 and Estate of Hardaway , 15 as the

basis for imposing the burden of proof against the nonowning spouse and treats the matter as settled Oklahoma law. 16 The Estate of Hardaway opinion, likewise, cites Templeton as its support, again treating the issue as settled law. 17 However, looking to the origin of this rule suggests that imposing the burden of proof on the nonowning spouse was not the settled law of Oklahoma prior to Thielenhaus . The Templeton opinion, upon which Thielenhaus relies, cites two sources as authority: Williams v. Williams 18 and a 1979 Oklahoma Law Review note on jointly acquired property. 19 However, the Williams opinion does not place the burden of proof for in-marriage enhance ment on the nonowning spouse,

property acquired during marriage is marital. 9 The burden to show otherwise is on the party claiming a separate property interest. 10 The transfer of separate property into shared ownership with a spouse is presumed to create marital prop erty. 11 The burden to prove other wise is on the spouse claiming that the property retained its separate character. 12 The spouse seeking to trace a separate property interest bears the burden to trace such property and prove that it remains separate. 13 Looking at these pre sumptions, the rule announced in Thielenhaus is wholly inconsistent with the remainder of Oklahoma’s equitable distribution law. By assigning the burden of proof to the nonowning spouse

Statements or opinions expressed in the Oklahoma Bar Journal are those of the authors and do not necessarily reflect those of the Oklahoma Bar Association, its officers, Board of Governors, Board of Editors or staff.

JANUARY 2026 | 17

THE OKLAHOMA BAR JOURNAL