The idea that property values can be discounted at death for a minority interest and for non-marketability is well established. Although discounting cannot be applied in addition to any reduction in value from special use valuation of land, discounting of corporate stock may produce a lower stock value than claiming special use valuation on the corporation -owned land.
Harl, Neil E.
"Discounting Property Values at Death,"
Agricultural Law Digest: Vol. 4
, Article 1.
Available at: https://lib.dr.iastate.edu/aglawdigest/vol4/iss24/1