The $330,000 result

An investor who automatically bought $500 of Vanguard's S&P 500 ETF each month since September 2010 would have roughly $330,000 today. That's the power of holding through crashes, pandemics, and market booms.

Why the S&P 500 keeps winning

The index is now a leveraged bet on five mega-cap tech stocks. Nvidia alone carries a five point two seven trillion dollar market cap, with Apple at four point eight five trillion, Alphabet at four point zero seven trillion, Microsoft at three point six eight trillion, and Amazon at two point seven seven trillion.

VOO: the anchor holding

Vanguard's flagship S&P 500 fund charges just 0.03% annually, holds 519 positions, and has returned 825% since launch. With 1.68 trillion in assets, it offers tight spreads and deep liquidity for retail investors.

IVV: the BlackRock twin

iShares Core S&P 500 ETF tracks the same index at the same 0.03% expense ratio. The choice between VOO and IVV depends on your brokerage platform and which fund's tax records are easier to manage.

SPY: liquidity king, cost laggard

The original S&P 500 ETF from 1993 charges 0.09% annually, triple VOO's rate. Its real edge is options depth and intraday liquidity for traders, not buy-and-hold investors.

SPLG: the dollar-cost averager's friend

State Street's SPLG tracks the S&P 500 at 0.03% but trades at a much lower share price. For investors without fractional shares, this means nearly the entire $500 monthly contribution gets invested instead of sitting in cash.

RSP: the equal-weight contrarian

Invesco's equal-weight S&P 500 ETF gives every stock roughly the same weight, rebalanced quarterly. Nvidia, Apple, and Microsoft become 0.2% positions instead of 7%. It's a hedge against concentration risk.

The concentration risk

Information technology now represents 38% of the S&P 500 by weight. If AI capex disappoints, antitrust action hits Alphabet, or any trillion-dollar name stumbles, cap-weighted funds like VOO will fall hard.

VOO's recent performance

VOO gained 18% over the past year and 13% year-to-date, reflecting the recent tailwind for mega-cap tech. But this concentration means a rerating of that group hits the fund hard.

Choosing your fund

For long-horizon investors in taxable accounts, VOO is the default. SPLG makes sense for small-dollar contributors without fractional shares. SPY belongs with active traders. RSP is for those concerned about concentration.

The overlooked detail

Share price matters more than it sounds. On platforms without fractional shares, a lower-priced fund like SPLG lets nearly your entire $500 monthly contribution get invested instead of sitting in cash waiting to accumulate.

“For an investor putting $500 a month into a brokerage that does not support fractional shares, SPLG lets nearly the entire contribution get to work each month rather than sitting in cash waiting for the next dollar to accumulate.”

The RSP hedge strategy

Owning RSP alongside a cap-weighted core is a defensible way to reduce reliance on five stocks while still capturing broad US equity returns. Size it according to your concentration concerns, not as a core replacement.