On March 5, 2017, the Hortons borrowed $100,000 against the equity in their personal residence with the loan secured by that home. In 2017, they were able to deduct the interest expense on this loan as home equity interest expense [an itemized deduction on Schedule A (Form 1040)]. The Tax Cuts and Jobs Act of 2017 disallows this interest expense deduction for 2018 through 2025. The Hortons’ CPA has asked them to review their financial records for February and March of 2017. They discover that they sold Disney stock on February 20, 2017, and used the proceeds to purchase Microsoft stock. Why is their CPA asking them for this information? How might this stock purchase in March 2017 help them obtain a deduction for all or part of the interest paid in 2018 and later on this home equity loan?

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Temp.Reg. § 1.163–8T and Reg. § 1.163–15.