Rational Security: Bye Bye, SPI (Dynamics...)
Well that's SPI getting acquired now by HP to follow on from IBM buying Watchfire
There may be loads of companies left in the security community waiting to get bought up, but there's only really Cenzic left of the original top 4 web application scanning tools left, and some other up-and-coming scanners like Acunetix WVS maybe as well.