This is a great question and one that should be addressed with a financial advisor. You are certainly permitted to consolidate your old 401(k) s into one IRA to make a particular investment or to hold all of your investments with one particular IRA company. That being said, many clients with self-directed IRAs maintain multiple IRAs, one with a self-directed firm for their alternative investments and others with brokerage firms, banks etc. to hold more conventional assets.