On: 37 YC Companies have valuations of or been sold for at least $40 Million

[rdl]

I think it's safe to assume the sum of current valuations is nearly 2x the valuation of dropbox+airbnb, or essentially the 30*40 + known big exits (~$600mm in total) + airbnb + dropbox, as a first approximation.

There's enough uncertainty in how accurate the individual valuation numbers are for airbnb, dropbox, and the 30x40 club to dominate the error.