It’s not about placards, sit-ins, and protest marches (although sometimes there can be a bit of all three). Ackman doesn’t just buy a couple of shares of the companies he invests in – he looks to buy up big meaty chunks, often becoming a business’s largest shareholder. 

That gives him a lot of influence over his investments: he’s able to get board seats, steer management in a certain direction, and generally use his financial clout to bend companies to his will. If that activist vision improves business performance, he adds value to his investments – and everyone’s happy.

Why should you care? Learning how masters of the craft work can be a great way to improve your own investing – as readers of our Warren Buffett Pack will already know.

Bill Ackman is a particularly good person to learn from: he’s super transparent about what he does and how he does it. And even when he messes up, he explains what he’s learned and how he’ll change. Better to learn from his mistakes than your own, right?

On top of that, you can actually buy a stake in Bill – his main fund, Pershing Square Holdings, is publicly listed on the Amsterdam and London stock markets, so if you like what you hear, you can share in his success. (The fund is straightforwardly invested in just nine stocks, and Restaurant Brands, Starbucks, Chipotle, Hilton and Lowe’s account for 75% of its assets.) As with anything, if you’re interested in investing in Ackman it’s sensible to learn how he thinks first – and the best way to do so is to look at his track record.

The takeaway: Bill Ackman is an activist value investor, who uses his influence to (try to) make companies better.