The Oklahoma Bar Journal January 2026

evidence to support the in-marriage enhancement, the amount of any jointly acquired increase is an issue of fact and within the discretion of the trial court. 29 Further, this note suggests (as was echoed in Templeton ) that the owning spouse must first show that the cause of the increase is due to “inflation or other circumstances beyond the parties’ control,” and only then must the nonowning spouse demonstrate that their efforts were “also a causal factor.” 30 This formu lation suggests a shifting burden of proof with respect to primarily passive separate assets. This state of law was recognized in Templeton , which advises: In order for a spouse to success fully prove that enhanced value is the result of joint endeavors, it must be shown that the net worth of the property increased during the marriage as the direct result of substantial contribution by the spouse of effort, skill or funds. 31

nor do any of the cases cited by Williams . 20 In-marriage enhancement is addressed in Williams. The Williams opinion reversed the trial court with respect to the parties’ homestead, part of which “was separate property inherited by defendant, but which appreciated substantially in value by reason of changing economic conditions and through these parties’ joint indus try,” while other portions were acquired jointly during the mar riage. 21 The Williams court held that “the lack of evidence” on the issue made it impossible to resolve. 22 The court remanded the issue for a new trial and directed that “any enhancement in value of the separate property resulting from joint efforts of the parties should be adjudicated by the trial court.” 23 The Williams court did not place the burden to show such enhancement on either party. Thus, the “burden of proof” rule ultimately cited in Thielenhaus does not have its ori gins in Williams . The other source cited by Templeton , a note from the Oklahoma Law Review , includes a discus sion of case law with respect to in-marriage enhancement. The note contains a passing comment (with out citation to legal authority) that provides, “When inflation or other circumstances beyond the parties’ control cause an increase in value of separate property, or income or profits from it, there is no jointly acquired property, unless the non-owning spouse can prove that his or her contributions were also a causal factor.” 24 This comment was later included, almost verbatim, in Templeton and appears to be the origin of the burden of proof rule, although it differs significantly from the rule in Thielenhaus . 25

Later in the note, the author suggests that the source of this rule may be the case of Kirkland v. Kirkland . 26 However, again, Kirkland does not allocate the burden of proof to the nonowning spouse. In that case, the court relied almost exclusively on evidence presented by the owning spouse, who testi fied that he did not invest any mar ital earnings in stocks inherited from his father and that the gains were purely from passive and market forces, while the wife pre sented little, if any, evidence on this issue. 27 The Kirkland opinion does not suggest that the wife, as the nonowning spouse, was required to meet any particular burden. This shifting burden approach is not a strictly accurate interpre tation of the then-existing case law. None of the cases cited in the discussion of in-marriage enhance ment place any special burden upon the nonowning spouse. 28 Rather, taken as a whole, the cases teach that while there must be

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.

18 | JANUARY 2026

THE OKLAHOMA BAR JOURNAL