Quote from tomahawk:
Of course spreading it around for less exposure to any individual firm is the obvious answer.
My problem is that I want to actively manage my retirement portfolio (IRAs), adjusting things sometimes as frequently as monthly. My first choice would be to use ETFs and trade through IB, but I already have my daytrading capital there, which would leave me overexposed to IB failure risk. The alternatives - Vanguard, Fidelity, etc. - charge an arm and a leg for commissions, and if you try to do it through mutual funds you run into redemption fees for holding less than 60 days.
So I'm stuck with the dilemma of having the majority of my capital at risk from some kind of disaster at IB, or paying up for the "security" of a bigger (non-public) name in the form of ridiculous fees, merely to implement a reasonably hands-on investment strategy.
Regarding SIPC, I think this has come up before, but at times one may want to be in all or mostly cash (or cash fund equivalent), potentially putting one over the $100k threshold for protection, even if spread across 3-4 firms.