The simple answer is anything is worth what a person is willing to
pay for it. With your theoreticl business you need to look at what
the business is. Is the building freehold or rented?
What capital assets does it have? (plant, macinery etc) What stock
does it have?
Is the business tied to the premises or is it relocatable? Balance
sheet? Competition/market share?
Importantly for businesses that dont have much in the way of assets
what is the goodwill? This is normally a financial measure of
customer and staff brand loyalty. A change of owner has a big effect
on this at the personal end of the market. Not so important when
Kraft bought out Cadbury for example but if the business you envisage
has key staff or customers who will leave then you are not really
going to pay a lot or possibly nothing for the goodwill.
The value of the stolen briefcase will be different to different
people. I used to own 2 pistols that had been used to kill people.
One was owned by General Urquhart who was in charge of the forces at
Arnhem in WW2, the other a pistol which someone committed suicide
with. They both have an intrinsic value-resale value for what they
are but the former also has an added value to collectors who would
like to possess an artifact from a remarkable historical time. There
are limits at both ends of the scale. The premium on top of the base
price is, if you like, the moral cost.