For a ramped-up bet on the stock market this year, it's hard to beat Affiliated Managers Group ( AMG). That's because this $9.5 billion financial firm has its hands in some of the most interesting corners of the money management business, an industry that sees its revenue base balloon when stock prices rise. That's a big part of why AMG has managed to rally more than 37% since the calendar flipped over to January. >>5 Heavily Shorted Stocks Hedge Funds Love AMG is unique because it doesn't actually manage money itself. Instead, Affiliated Managers holds ownership stakes in a collection of small to midsized boutique investment managers. Because AMG's interests are spread across a large number of firms, it's able to get exposure to a broader basket of specialized asset classes than a single firm could. While that does mean that AMG foregoes some cost savings by replicating many roles at each firm, the lack of a centralized investment edict from the top means that clients can have exposure to uncorrelated strategies at AMG's firms and the firm can collect higher fees. Affiliated has rallied so hard in 2013 for a very simple reason: as all of the assets that its clients own climb during this rally, the firm gets to multiply its management fees across a bigger pool of cash. In my view, the stock market isn't showing too many cracks just yet -- and AMG should continue to benefit as a result.