Index investing has established itself as one of the most effective long-term strategies available. With low fees, extensive diversification, and consistent exposure to America's largest corporations, it has enabled millions of retirement savers to accumulate wealth through their 401(k) plans. However, passive investing comes with an often-overlooked drawback: index funds do not have the discretion to choose their holdings. Consequently, millions of 401(k) investors find themselves owning shares of SpaceX, which has already led to a loss of $1.4 billion.