Wis. Stat. § 766.63
Marital property presumptions and tracing principals are applied. In Matter of Estate of Lloyd, 170 Wis. 2d 240, 487 N.W.2d 644 (Ct. App. 1992). If tracing of the marital component of a mixed asset is established under sub. (1) reclassification does not occur. Instead, a claim for reimbursement exists in favor of the marital estate measured by the enhanced value of the asset, not the marital amounts expended. Estate of Kobylski, 178 Wis. 2d 158, 503 N.W.2d 369 (Ct. App. 1993). Under sub. (2) a party who applies substantial uncompensated labor to property may not recover if there is no resulting substantial appreciation. Estate of Kobylski, 178 Wis. 2d 158, 503 N.W.2d 369 (Ct. App. 1993). Expenditures that result in the mere maintenance of property, including the payment of property taxes, do not result in marital property being created through mixing. Krueger v. Rodenberg, 190 Wis. 2d 367, 527 N.W.2d 381 (Ct. App. 1994). If a nonmarital asset is mixed with marital property, tracing the nonmarital property to its nonmarital source preserves the traced component's nonmarital status. There is no requirement that the party tracing the nonmarital component also trace the mixing of the marital component. That the marital property was used to satisfy a nonmarital debt against the property does not change the nonmarital character of the traceable property. Bille v. Zuraff, 198 Wis. 2d 867, 543 N.W.2d 568 (Ct. App. 1995), 95-0007. What Part of Yours is Mine?: The Creation of a Marital Property Ownership Interest by Improving Nonmarital Property Under Wisconsin's Marital Property Law. Knauss. 2005 WLR 855.