On valuation of private companies...

Valuation generally tends to be a complicated topic.  Often wall street analysts use their own models, comparables, and multiples to assess value of companies and shares.  But in case of private companies, valuation involves a lot of judgement/subjectivity.  Often value of private company shares is determined based on: 1) the last fund raise, or 2) independent valuers (that provide a 409A valuation report), or 3) (worst) a judgement call by the founders.  None of these are overly reliable.  Last fund raise value could be inflated depending on the excitement of the investor, or the true value of the business could, in reality, be lowered by other structural nuances.  The investor could've asked for anti-dilution clauses (to cap their downside risk - indicating that the value at which they've invested is inflated), or could've received warrants (which, when liquidated, lowers the per share value).  The independent valuers report is usually skewed by level of optimism shown by the management's projections, and the founder call is the least reliable.  

Of these, 409A report should be considered more reliable of the three (especially when the last fund raise happened a while back).  This report, even though based on management's projections, is subject to statutory audits and auditors will question material under achievement to the projections in 409A.  It's because of this very reason, 409A valuations are determined using conservative projections - projections that are closest to expected reality.