The Oklahoma Bar Journal January 2026

and furthers modern policy approaches to the marriage relation . Under the source of funds rule, the process of acqui sition of property is an ongoing process. Therefore, the increase in property acquired during marriage seems to require this placing of the burden of proof. 33 Thus, the shifting burden set forth in Templeton , which applied only where there was evidence of primarily passive apprecia tion, appeared to be the law, but the presumption with respect to non-passive increases remained unresolved. In the absence of evidence that the increase in value was created by passive growth, such increases should – consistent with Oklahoma law – be treated presumptively as jointly acquired. In 1994, the Oklahoma Supreme Court released Estate of Hardaway . 34 The shifting burden set out in Templeton was significantly truncated; rather than expressing the shifting burden outlined in Templeton , the Hardaway court simply stated, “The burden of proof is upon the non-owning spouse to prove such enhancement is the result of joint endeavors,” relying on Templeton as authority for this rule. 35 This pronouncement significantly changed the prior rule, as it does not require proof of passive increases and does not shift the burden but instead places the entire burden on the nonowning spouse from inception. Notably, the Hardaway opinion does not suggest any intent to depart from Templeton ’s passive asset/shifting burden approach. 36 This apparently inadvertent refram ing would have significant conse quences for Oklahoma family law. The next year, the Hardaway “burden of proof” formulation,

which placed the burden of proof on the nonowning spouse from inception, became the version adopted in Thielenhaus , rather than the more nuanced shifting bur den version set out in Templeton . 37 The requirement that there must be evidence that the increase in value was primarily due to passive forces was eliminated; the new rule placed the burden of proof entirely on the nonowning spouse, even in cases where the evidence suggested appreciation was pri marily or entirely the result of joint efforts. The Thielenhaus opinion then applied this new burden of proof to the newly emphasized “three critical value elements” and placed that burden solely on the party seeking to prove in-marriage enhancement, without any require ment that the owning spouse prove the existence of any passive appre ciation. 38 Following Thielenhaus , the nonowning spouse was required to show the value at the time of marriage and the value at the time of divorce; tie the increase in value to the funds, skills or efforts of the parties; and exclude growth gen erated by passive forces. If any of these elements are not satisfactorily proven, the entire increase would be awarded to the owning spouse as separate property. 39 This newly created presumption and allocation of the burden of proof were a significant departure from existing law . However, it is not clear that Thielenhaus was actually intended to alter prior law. The opinion does not indicate that any intent to depart from Templeton and even cites Templeton as support for the burden of proof. 40 This burden of proof rule can be traced from Kirkland and Williams , which created a shifting burden approach where evidence showed

The language of the opinion is phrased neutrally, using “it must be shown” rather than language sug gesting that it must necessarily be shown by the nonowning spouse. Thus, the language of Templeton does not assign the burden of proof to the nonowning spouse. At most, Templeton suggests a shifting bur den approach, where the owning spouse must first demonstrate that the increase is the result of pas sive forces before the nonowning spouse must present evidence of joint efforts. While the shifting bur den was not necessarily set out in prior case law, it was attributed to the Williams case and was adopted as if it were settled law by the Templeton opinion. At the time Templeton was decided, there does not appear to have been any recognition that the opinion intended to apply a particular presumption or burden of proof to in-marriage enhance ment. Supreme Court cases fol lowing Templeton did not interpret Templeton as placing the burden of proof on the nonowning spouse. 32 In 1988, following Templeton in 1982 but prior to Thielenhaus in 1995, Professor Robert G. Spector wrote that existing Oklahoma law favored a presumption that in- marriage enhancement was mari tal, but treating the issue as unde cided in Oklahoma law: Many states apply a presump tion that property acquired during the marriage is marital. Therefore, in the absence of evidence that inflation or other natural market conditions caused the increase in value of the separate property, the entire amount is presumed to be marital. This approach clearly favors the marital estate

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 | 19

THE OKLAHOMA BAR JOURNAL