I don't believe there would be any case law only statutory law since the provisions posted by @R-SchuleCPA never came into play. If you follow the notes in the law (here) and read the referenced Public Laws and amendments you will find that subsection (d)(11) which was originally (d)(9) was enacted in 2001 but was only to affect property of decedents dying after Dec 31, 2009. However, on Dec 17, 2010 Public Law repealed subsection (d)(11) formerly (d)(9) for decedents dying after Dec 31, 2009.
As @Anonymous_ states the using the step up basis on the date of death is the correct method.
@mjwoo94015
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