Unlike a market-cap-weighted stock index driven by competition, an aggregate bond index is dominated by the largest issuer: the U.S. government. The index mechanically buys whatever debt the government issues, regardless of duration risk or investor interests.
Most of an index's returns come from a tiny fraction of its component stocks (e.g., 7% of the Russell 3000). The goal of indexing isn't just diversification; it's a strategy to ensure you own the unpredictable "tail-event" winners, like the next Amazon, that are nearly impossible to identify in advance.
Contrary to popular belief, the market may be getting less efficient. The dominance of indexing, quant funds, and multi-manager pods—all with short time horizons—creates dislocations. This leaves opportunities for long-term investors to buy valuable assets that are neglected because their path to value creation is uncertain.
Market-cap-weighted indexes create a perverse momentum loop. As a stock's price rises, its weight in the index increases, forcing new passive capital to buy more of it at inflated prices. This mechanism is the structural opposite of a value-oriented 'buy low, sell high' discipline.
In a market where everyone is chasing the same high-quality corporate bonds, driving premiums up, a defensive strategy is to pivot to Treasuries. They can offer comparable yields without the inflated premium or credit risk, providing a safe haven while waiting for better entry points in credit markets.
Despite recent concerns about private credit quality, the most rapid and substantial growth in debt since the GFC has occurred in the government sector. This makes the government bond market, not private credit, the most likely source of a future systemic crisis, especially in a rising rate environment.
In bond investing, where upside is capped at a promised return, superior performance comes from what you exclude, not what you buy. The primary task is to eliminate the bonds that will default. Once those are removed, all the remaining performing bonds deliver a similar, contractually-fixed return.
BlackRock's CIO of Global Fixed Income argues that unlike equities, fixed income is about consistently getting paid back. The optimal strategy is broad diversification—tilting odds slightly in your favor and repeating it—rather than making concentrated, high-conviction "bravado" bets on specific market segments.
Since 2022, highly leveraged hedge funds have bought 37% of net long-term Treasury issuance. This concentration makes the world’s most important market exceptionally vulnerable, as any volatility spike could trigger forced mass selling (degrossing) from these funds.
For 40 years, falling rates pushed 'safe' bond funds into increasingly risky assets to chase yield. With rates now rising, these mis-categorized portfolios are the most vulnerable part of the financial system. A crisis in credit or sovereign debt is more probable than a stock-market-led crash.
Enormous government borrowing is absorbing so much capital that it's crowding out corporate debt issuance, particularly for smaller businesses. This lack of new corporate supply leads to ironically tight credit spreads for large borrowers. This dynamic mirrors the intense concentration seen in public equity markets.