Yeah somewhere around Series A and esp Series B chances are, unless the founders really lucked out (eg, equity funding that could have been a debt round due to insane profits), they'll have lost control
shares: preseed / seed / A / option pool + multiple cofounders means CEO is a minority holder, and common may be as well. for firms raising big seeds, I expect even more likely at the A.
board: many co's give 1 board seat at Seed and another at A, so lose the board around B. but more negotiable, eg, seed investor gives seat to later investor .
So it seems normal: for most, somewhere between A + B, and except for outliers, by C.
Edit: VCs generally have an ownership target, say 15% as a lead, and less as a follower. So that adds up quickly.
