So I'm in the process of getting rid of high expense ratio target date funds from my employer(which annoying eat most of the matching). I want to buy Vanguard, but more then 50% of my net worth is already in Vanguard indexes. Is there some danger of not diversifying what companies invest my money? There was some noise last year of tax issues with vanguard. I would hate to have a huge assessment or fee on all of my investments. Seems against diversification theory.