They could be interchanging Sony for the BDA, much like most articles concerning the format war do. Considering the fact that Matsushita (Panasonic) has more to gain from a Blu-Ray victory than Sony does, and considering the fact that they are by far the largest CE in Japan, it's more likely that they paid the $400 mil. than Sony.
Actually, it's more likely that many companies from the BDA contributed to the $400 mil.
That is assuming that these reports of a payoff are correct.