Ask TheStreet: Delistings

The outperformance became even more acute this past February when BlackRock agreed to merge with Merrill Lynch's(MER Quote) money management division to form a new company with nearly $1 trillion in assets. PNC will maintain a 34% stake in the new company, but an investor would have been better off holding a piece of BlackRock than PNC.

The bottom line is that you need to do the same homework you would do when looking into investing in any stock and determine if you'd rather focus your money on one piece of a company or the whole shebang.