Shares of the Swiss National Bank have been on a tear this week after the central bank said it expected to report a 2017 profit of 54 billion francs ($55 billion). SNB shares were up 5% midday Friday at 4,800 francs, a record, capping a three-day surge of 17%. It raises a fascinating question: why own shares of a central bank? The SNB is a rare breed of central banks—than includes those in Belgium and Japan—that even have listed shares. For the SNB the answer is simple: it is a very large money manager—which about 760 billion francs worth of foreign stocks and bonds—and gets to print its own money. That’s a recipe for success. But on the negative side, private shareholders of the SNB don’t have the same kinds of rights and profit potential that investors of other banks and companies have. Other than a tiny dividend, not entirely clear what shareholders actually own. With that backdrop in mind, here are five things to know about the SNB and its shares. Why is the SNB making so much money? The SNB is trying to weaken the Swiss franc. To do that, it prints new francs and sells them in the markets. What it ends up with in return is a vast pile of foreign stocks and bonds. So long as people still want Swiss francs–and they tend to want them especially in times of global stress–it’s quite a business model. Its efforts to weaken the franc showed some success last year with the euro strengthening about 10% against the franc. That makes the SNB’s investments worth a lot more when converted back into Swiss francs. Has this always been the case? No. In 2015 the SNB lose more than 23 billion francs because the franc strengthened after the SNB abandoned a longstanding ceiling it had maintained on the currency’s value. Still, in three of the last four years the SNB has earned big profits. Who owns its shares? There are 100,000 shares of the SNB. At the end of 2016, Swiss states, known as Cantons, and Cantonal banks owned a combined 52,000 shares and 75% of voting shares. Private shareholders owned 48,000 shares but only 25% of voting shares. The largest single shareholder at the end of 2016 was a German investor. Just as interesting is who doesn’t own shares: the SNB’s own governing council, according to the last annual report. An alternate board member owned one share. How liquid is the stock? Not very, making it hard to load and unload vast sums. Only around 200 shares trade hands a day, which is one reason why the stock is volatile; it doesn’t take a lot of trades to move the price. How about its dividend? This is the biggest reason why the SNB’s sky-high share price is such a headscratcher: the dividend is capped at a puny 15 francs a share, which comes to a yield of about 0.3%. The dividend amount is fixed by law, so it doesn’t matter much money the SNB makes, investors only get a tiny slice of the pie.