Their base salary (which is what is listed here) may not be a whole lot more; a large portion of their compensation comes in the form of annual bonuses. That's

Their base salary (which is what is listed here) may not be a whole lot more; a large portion of their compensation comes in the form of annual bonuses. That's also the case for some of the listed firms, FWIW. As a senior engineer at one of them, I have received bonuses that are twice my "base salary" in good years.