When shares move between people who know each other well, there is no open market to set the figure. A valuation report supplies one, with the reasoning that supports it.
Why it matters
A transfer between family members or partners can have tax consequences. A figure that cannot be explained invites questions; one that sets out its method and assumptions answers them in advance.
What we need
Three years of financials, the share structure, and the date the transfer takes effect, which usually becomes the valuation date.