This is true from a pure accounting perspective. In reality, if a company only has discounted cash flows to imply a $1b valuation but sells for $10b, there must

This is true from a pure accounting perspective. In reality, if a company only has discounted cash flows to imply a $1b valuation but sells for $10b, there must be something to explain that difference. In accounting, it's just an equation to make things balance. However, for the firm who decided to offer $10b, there is clearly some additional value they are applying to the $1b book.