United States Tax Court ruled in the case of Denise Celeste McMillan v. Commissioner of Internal Revenue on August 26, 2019. That her horse business no longer existed with the death of her last horse. Ms. McMillan challenged the IRS on disallowing her deductions for her horse showing/breeding business. Ms. McMillan was self-employed, both as a horse breeder and trainer and as an independent IT professional. During the 2010 tax year, she claimed a deduction for her horse business, which functionally no longer existed due to the death of her last horse. Proving that not only can you not beat a dead horse but also that a horse business lives and dies with the horses.
For the complete decision see T.C. Memo. 2019-108.