Wieviel sind Minderheitsbeteiligungen wert?
Wieviel Wertsteigerung bringt Börsengang?

according to Shannon Pratt

The discounts are taken in chain, that is, they are multiplicative, not additive:

Controlling interest value $100 per share
Less: 30% minority discount 30

Value if publicly traded $ 70 per share

Less 40% discount for lack
marketability 28 per share

Closely held minority value $ 42 per share