And neither is rationality absolute nor consistent. One company can exhibit rational behavior while attracting investors, while a different company does not. A single companies can be rational at times and irrational at other times. And quite often companies will behave in extremely dumb ways. Especially in our current economic system where the cost of being dumb is negatively correlated with the amount of money available to you, and that cost goes down on a sigmoid curve.
Note that the cool thing about rationality is that it does not depend on transitivity. If what companies do to attract investors works, then it is in fact rational of them, regardless of the rationally of investors.