Investing & Retirement
Roth IRA, 401(k), index funds — decisions you make once a decade.

Investing decisions in a US tax-advantaged account context are dominated by a handful of high-leverage choices that an individual investor makes a small number of times across an entire lifetime: which account types to fund and in what order, which broker to custody them at, which broad-market funds to hold, and how to allocate between stocks and bonds as a function of age and risk tolerance. Getting these four decisions roughly right matters more than nearly anything tactical that happens day-to-day in the market.

This section covers the US-specific structural features that make investing decisions in America different from anywhere else in the world: the Roth IRA (post-tax contributions, tax-free growth, no required minimum distributions on the original owner), the 401(k) employer match (the single highest-ROI dollar most US workers will ever encounter), the mega backdoor Roth (a planning loophole allowing up to roughly $46,500/year in additional Roth contributions for employees of plans that permit it), the Health Savings Account (the only fully triple-tax-advantaged account in the US code), and the brokerage cash-sweep options that affect every dollar held at a major US broker. We treat each at the level of the actual decision a reader faces, not at the level of generic explainer content.

Three structural facts anchor every recommendation in this section. First, expense ratios compound. A 1% annual fund fee over 40 years consumes roughly a third of total return; a 0.04% fee on a Fidelity total-market index fund consumes essentially none of it. The choice of fund matters in a way that is hard to overstate, and the difference between flagship low-cost index funds at the three major US brokers is small enough that broker selection is largely a question of ergonomics rather than performance. Second, the tax-advantaged account hierarchy is genuinely worth understanding: the math behind funding HSA before 401(k) before Roth IRA is non-obvious until you work through it, and it differs by tax bracket. We publish the full math, not just the conclusion. Third, the Roth-vs-Traditional decision depends on your marginal tax bracket now vs in retirement. The conventional rule of thumb ("Roth when young, Traditional when old") is wrong about half the time once you account for likely tax brackets, Social Security taxation, RMD effects, and state tax considerations.

What this section will not do is publish predictions about which sector or stock will outperform next year, or rank actively managed funds against each other. The overwhelming weight of US academic and industry evidence — SPIVA, Morningstar, S&P persistence scorecards — points in the same direction: an individual investor's edge comes from low costs, tax efficiency, asset-class diversification, and behavioral discipline. Everything in this section is designed around amplifying those four levers, not promising shortcuts that the data does not support.