Bel-Air Dead, by Stuart Woods. Unabridged audio.
I am a big fan of Woods' works, and of his Stone Barrington novels in particular. And this is one of his best.
All of Woods' series take place in the same world, and there have been occassional cross-overs, but this is the most fully integrated mashup I've read. Stone Barrington is called out to the West Coast to help old friend Arrington Calder keep her stake in her movie studio, fighting off a takeover attempt that takes a very dangerous turn. It turns out that the man behind the takeover attempt is in league with the former wife of Ed Eagle, the protagonist of another series of Woods novels. Eagle himeself takes an active role in this novel, and that subplot is essentially a sequel to his last novel. This crossover was very well done.
I do want to point out that the business/stock aspects of the book were handled properly, and that the basic facts of that subplot were accurate.
There is also a change in Barrington's employment status in this novel, which is a natural progression from the last 5 or so of his adventures. Woods is skilled at handling the progression of events in the "long arc" of his characters lives, while making each particular novel a stand-alone book.