When I first began paying attention to exchange-traded funds, I viewed them as financial plumbing. They were useful, efficient, and not particularly exciting. An ETF allowed me to buy a basket of securities without selecting every stock or bond myself, and that seemed like a sensible improvement over building a portfolio one company at a time. What I did not fully appreciate was that the plumbing would eventually become some of the most valuable infrastructure in global finance. ETFs have moved from the margins of investing to the center of it. They sit in retirement accounts, brokerage portfolios, institutional strategies, model portfolios, robo-advisory platforms, and short-term trading systems. They are used by people investing $50 from a paycheck and institutions moving billions of dollars before lunch. BlackRock, through its iShares franchise, has become one of the clearest beneficiaries of this transformation. By the end of 2025, BlackRock had approximately $14 trillion in total ...