I've noticed that a number of other YC partners frequently do investing outside of the biannual YC batches, mostly as follow ups, but it doesn't seem like you do much of that yourself.<p>Why not?
IANPG:<p>Perhaps because his strategy is to maximize his odds of investing in an extreme outlier, and because later round investments are several times more expensive than YC's initial investment, follow on investments reduce the odds of hitting an extreme outlier by that factor - e.g. an additional 5% of a company with a moderate chance of a moderate exit is worth less than 5% of ten companies which might have huge exits.<p>Or rather that may be the case when pursued at the scale of YC's portfolio - i.e. foregoing 10 follow on investments for 100 new ones.<p>It also might be the case that follow on investing by PG would adversely impact the YC brand's reputation both with potential founders and the network of investors with whom they have established relationships because there might be the perception that YC is less focused in the first case and a competitor in the second.