In the latest look at stocks ordered by largest market capitalization, Russell 3000 component Penumbra Inc (PEN) was identified as having a larger market cap than the smaller end of the S&P 500, for example Invesco Ltd (IVZ), according to The Online Investor. Click here to find out the top S&P 500 components ordered by average analyst rating » Market capitalization is an important data point for investors to keep an eye on, for various reasons..