· Updated March 2026 Best S&P 500 Index Funds 2026: VOO vs IVV vs SPLG vs SPY
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Best S&P 500 Index Funds 2026: VOO vs IVV vs SPLG vs SPY

S&P 500 Funds Interactive Comparison

TickerFund NameTypeExpense RatioAssets (AUM)Tracking DiffSpreadMin Invest

Data scraped and verified for 7 funds. Null over fake data, always.

The Heavyweights: VOO vs SPY vs IVV

Vanguard S&P 500 ETF
VOO

Vanguard's VOO remains the gold standard for long-term buy-and-hold investors. With a rock-bottom expense ratio of 0.03%, incredibly tight tracking to the index, and a structural focus on minimizing tracking error, it's arguably the best overall choice. Its only downside is a higher per-share price compared to SPLG, which matters less if your broker supports fractional shares.

iShares Core S&P 500 ETF
IVV

BlackRock's IVV is virtually identical to VOO in cost (0.03%) and performance. It frequently engages in securities lending slightly more aggressively than Vanguard, which sometimes allows it to slightly outperform the index to cover its own fee. Between VOO and IVV, choose the one your broker offers without transaction fees or prefer based on brand loyalty.

SPDR S&P 500 ETF Trust
SPY

The original ETF. SPY is uniquely structured as a Unit Investment Trust (UIT). This means it cannot reinvest dividends paid by underlying companies until it pays them out to shareholders (cash drag), and it charges a significantly higher 0.0945% expense ratio. For buy-and-hold investors, SPY is objectively worse than VOO or IVV. However, SPY boasts the highest trading volume and most liquid options chain in the world, making it the undeniable king for day traders and options sellers.

State Street SPDR Portfolio S&P 500 ETF
SPLG

The dark horse. SPLG is State Street's low-cost answer to VOO and IVV. It holds the exact same index as SPY but operates under a modern ETF structure and charges a category-leading 0.02% expense ratio, officially making it the cheapest S&P 500 ETF. Its lower share price also makes it highly accessible for smaller investors without fractional share access.

Mutual Funds: SWPPX vs FXAIX vs VFIAX

If you are investing through a 401(k) or prefer the simplicity of automatic fractional investing at exactly the end-of-day NAV, mutual funds are the way to go.

Frequently Asked Questions

What is the best S&P 500 index fund 2026?
The best S&P 500 index fund depends on your account type. For ETFs, SPLG is currently the cheapest with a 0.02% expense ratio. For mutual funds, FXAIX leads with a 0.015% expense ratio. However, VOO and IVV are also excellent choices with 0.03% expense ratios and massive liquidity.
VOO vs SPY vs IVV: Which is better?
For long-term investors, VOO and IVV are better than SPY. VOO and IVV have an expense ratio of 0.03%, while SPY charges 0.0945%. SPY is better suited for active day traders and options traders due to its unparalleled liquidity.
What is the cheapest S&P 500 ETF?
As of 2026, the State Street SPDR Portfolio S&P 500 ETF (SPLG) is the cheapest S&P 500 ETF with an expense ratio of just 0.02%.
Should I buy an S&P 500 ETF or Mutual Fund?
ETFs (like VOO or SPLG) are generally more tax-efficient in taxable accounts. Mutual funds (like FXAIX or SWPPX) allow for exact dollar-amount investing and automatic investments, making them ideal for tax-advantaged retirement accounts like a 401(k) or IRA.
Why are SPY fees higher than VOO and IVV?
SPY is structured as a Unit Investment Trust (UIT), which is an older, less flexible structure that cannot reinvest dividends easily and carries higher administrative costs compared to modern ETFs like VOO and IVV.

Data Sources & Methodology

ETF data sourced from fund prospectuses, SEC filings, and financial data aggregators. Expense ratios, holdings, and performance figures are updated periodically and may reflect slight delays from official filings.

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