I'm rounding out a big week of buying for the defensive value investing portfolio that I manage on behalf of the Fool, but not before I add one more name to the list. Today, I'll be scooping up shares of payroll processing powerhouse Paychex (PAYX -1.44%). Like many of the companies I hold in the portfolio, this is the kind of company that should thrive in all market environments. Most importantly, Paychex is the model of consistency, absolutely dominating its niche by providing a service that makes doing business easier for other companies. This is the kind of efficiency booster that helps keep its customers coming back year after year. It's also a dividend powerhouse to boot. In the video below, I break down my investment thesis in greater detail about why I want to own this company today.