Alex: Here's a riddle for you. A farmer in Argentina sells soybeans to a buyer in China, and the price is set in the currency of a third country that neither of them lives in. What currency is it?
Jordan: That's got to be the United States dollar.
Alex: Exactly. And it's strange when you think about it. Neither party is American, the soybeans never touch American soil, and the entire deal still runs on dollars. Today we're answering one question: how did one country's money become the whole world's money, and what does that mean for every investment you will ever make?
Jordan: I always knew the dollar was the global currency, but I never stopped to ask why everyone just agreed to it. Nobody signed a treaty, right?
Alex: Actually, they kind of did. The story starts in nineteen forty-four, near the end of World War Two, at a hotel in Bretton Woods, New Hampshire. Forty-four nations sat down to rebuild the world's money from scratch, and they made the dollar the anchor. The United States promised to convert dollars into gold at thirty-five dollars an ounce, and every other major currency pegged itself to the dollar.
Jordan: So the dollar was basically gold, but easier to carry.
Alex: That's exactly how it worked for almost thirty years. But promises are easy until they're expensive. By the late nineteen sixties, America was spending heavily on a war in Vietnam and big domestic programs, dollars were flooding overseas, and foreign governments started knocking on the door asking for their gold. There wasn't enough gold. So on August fifteenth, nineteen seventy-one, President Nixon closed the gold window, just like we talked about in Chapter one.
Jordan: And I would have guessed that was the end of the dollar's reign. If the dollar wasn't backed by gold anymore, why would anyone keep using it?
Alex: That's the twist. The gold backing died, but the dollar's dominance didn't. Because in the meantime, something else had happened. In the nineteen seventies, the United States struck understandings with the big oil-producing nations: sell your oil in dollars, and park your profits in United States Treasury bonds, and in return you get American security guarantees. Since oil is the one commodity every country on Earth has to buy, that deal guaranteed permanent global demand for dollars.
Jordan: So every country needs oil, oil is priced in dollars, so every country needs dollars. That's the petrodollar.
Alex: That's the petrodollar. And it layered on top of the network effect that was already there. Think back to Chapter one: money works because everyone else uses it. The dollar had a thirty-year head start as the world's anchor, and once exporters, importers, banks, and central banks were all running on dollars, switching became impossibly expensive. Nobody wants to be the first to leave the system that everyone else uses.
Jordan: Okay, so history explains how it happened. But why does it stay? What keeps the dollar on top today?
Alex: Three things. First, trust and the rule of law. When a central bank in another country stores its rainy-day fund, it wants to know the rules won't change overnight and nobody will seize the money for political reasons. United States institutions aren't perfect, but they are the deepest bet in the world. Second, liquidity. The market for United States Treasury bonds is the deepest, most liquid market on the planet. If you need to park a hundred billion dollars somewhere safe and sell it tomorrow, there is exactly one market that can handle that. Third, there is simply no alternative that offers all of this at once.
Jordan: Can I pin down one phrase before we move on? When people say reserve currency, do they literally mean central banks holding piles of dollars?
Alex: Literally, yes. Well over half of all the foreign exchange reserves in the world, the rainy-day funds that central banks hold for emergencies, sit in dollars and United States Treasury bonds. And the vast majority of international trade is invoiced in dollars too. So a reserve currency just means the money the world trusts enough to save in and trade in.
Jordan: Wait, but I keep hearing about challengers. The euro, the Chinese yuan, the BRICS countries talking about trading without the dollar. Is that all noise?
Alex: It's not all noise, but it's mostly overblown. The euro is a real second-place currency, but Europe doesn't have one unified bond market the way America has Treasuries. The yuan is growing in trade, but China controls the flow of money across its borders, and nobody builds their life savings in a currency the government might not let them move. And the BRICS talk a lot about de-dollarization, but they can't agree on what would replace the dollar. The dollar's share of global reserves has slipped over the decades, yet no rival has come anywhere close to replacing it.
Jordan: So the dollar wins by default. Nobody else is even qualified.
Alex: Pretty much. Now, here's where it gets interesting for you as an investor. Being the world's currency gives America what a French finance minister in the nineteen sixties called an exorbitant privilege. The United States borrows in its own currency, so it can never be forced into default the way a country that borrows in someone else's money can. And because the whole world needs dollars, America borrows more cheaply than anyone else on Earth.
Jordan: That sounds like a pretty sweet deal. Is there a catch?
Alex: There is, and an economist named Robert Triffin spotted it in the nineteen sixties. Here's the dilemma. The world needs a constant supply of dollars to trade, so the United States has to run trade deficits, sending dollars abroad year after year. But if those deficits grow forever, the world starts doubting whether the dollars are sound. To supply the world with dollars, America must weaken its own finances. That's the Triffin dilemma, and it never got resolved. It just got managed.
Jordan: And I guess there's another power that comes with this: if the whole world runs on your money, you can cut people off from it.
Alex: That's the weaponization part, and it's the reason some countries want out. After Russia invaded Ukraine in twenty twenty-two, the United States and its allies froze Russia's dollar reserves and cut its banks off from the dollar payment system. It worked as punishment, but it also sent a message to every other country: your dollar savings are only yours as long as Washington says so. That's a big reason central banks have been buying gold at a record pace in recent years.
Jordan: Okay, this is the macro history, but how does any of this touch my portfolio? I'm not a central bank.
Alex: It touches everything, because the dollar is the denominator of the world. Let me give you this week's example. The dollar index is sitting around one hundred one, its strongest since July. Why? Because the Fed hiked rates on September sixteenth to a range of three point seven five to four percent, the first hike in three years, and the ten-year Treasury yield is around five point one seven percent, the highest since two thousand seven. Higher American rates pull global capital into dollars, and the dollar rises.
Jordan: And a rising dollar does what, exactly?
Alex: Three things, and you can see all of them right now. First, commodities get squeezed. Gold and oil are priced in dollars, so when the dollar strengthens, they get more expensive for every buyer using another currency, and demand softens. Gold is heading for a weekly loss near four thousand two hundred eighty-eight dollars an ounce, partly on that stronger dollar. Second, American multinationals take a hit, because their overseas profits are worth fewer dollars when converted home. Third, and this is the brutal one, emerging markets get crushed. Countries and companies that borrowed in dollars suddenly owe more in their own currency terms. A strong dollar has triggered an emerging market crisis more than once in history.
Jordan: So when I hear the dollar is strong, that's good for my vacation in Europe, but bad for a lot of my investments.
Alex: That's the right intuition. A strong dollar is great for American travelers and importers, and it's a headwind for exporters, commodity producers, and emerging markets. And the reverse is true too. When the dollar weakens, commodities rally, emerging markets breathe, and American exporters get a tailwind. Every asset class you will ever study in this book, from stocks to bonds to Bitcoin, has a dollar tide underneath it.
Jordan: That's making me look at the dollar index the way I look at the weather. You don't control it, but you'd better check it before you go out.
Alex: I love that analogy. And here's one more thread to file away. Back in Chapter one, we built a scorecard for what makes good money: scarce, durable, portable, divisible, and widely accepted. The dollar aces the last one and fails the first. Way down the road, in Chapter twenty-seven, we'll grade Bitcoin against that same scorecard and ask whether a money that belongs to no country could ever do the job the dollar does today.
Jordan: Let me try to recap, and you tell me if I've got it. A reserve currency is the world's shared money, the operating system everything else runs on. The dollar got there through Bretton Woods in nineteen forty-four, survived the end of gold in nineteen seventy-one, and got locked in by the petrodollar deals of the nineteen seventies. It stays on top because of trust, the rule of law, and the deepest bond market on Earth, and because no rival offers all of that at once. America gets the exorbitant privilege of borrowing cheap in its own currency, plus the power to cut enemies off from the system, but it pays with the Triffin dilemma of permanent deficits. And for my portfolio, the dollar is the tide: when it rises, commodities and emerging markets struggle, and when it falls, they rally.
Alex: That's a perfect recap. You've got all of it. And now the one key takeaway for this chapter, stated plainly: the dollar is the world's shared money operating system, and when it moves, every price on the planet has to move with it. Watch the dollar, and you'll see the tide before it reaches your portfolio.
Jordan: That's going to change how I read the financial news. The dollar index just became part of my morning routine.
Alex: Good. Next chapter, we start Part Two of the book: How Markets Work. Chapter seven is called Stocks: Owning a Slice of a Business, and we'll finally answer the most basic question in investing: when you buy a share of a company, what do you actually own? You're going to love it.