SPLG vs VOO vs IVV: A Quant's Guide to the Cheapest S&P 500 ETFs

Over $1.5 trillion. That’s the colossal sum investors have poured into just three S&P 500 index funds. Vanguard’s VOO, iShares’ IVV, and State Street’s SPLG stand as the undisputed titans of the market. They all track the same 500 companies. They all have nearly identical fees. So, does it even matter which one you choose? It absolutely does. This analysis dissects the SPLG vs VOO vs IVV debate, digging far beyond the sticker price to rank these funds on total cost, performance, and real-world value for the modern retail investor.

Forget just the rock-bottom expense ratios. We’re diving into the hidden mechanics that truly drive returns: subtle tracking errors, the friction of bid-ask spreads, and the often-overlooked revenue from securities lending. These are the critical details that create small, compounding differences in

The Three Behemoths of the S&P 500

Let's meet the contenders. These three ETFs all aim to do the same thing: mirror the S&P 500. But they come from different fund families, each with its own unique story and strategy.

• VOO (Vanguard S&P 500 ETF): Vanguard practically invented low-cost index investing. VOO is one of its crown jewels. The company's unique client-owned structure is built to keep fees low, making it a go-to choice for long-term investors.
• IVV (iShares CORE S&P 500 ETF): BlackRock's iShares is the biggest ETF provider on the planet. IVV is a pillar of its "Core" series, famous for its deep liquidity and tight index tracking. It's a favorite of financial advisors and large institutions.
• SPLG (SPDR Portfolio S&P 500 ETF): State Street (SSGA) created SPY, the world's very first ETF. SPLG is their lean, low-cost answer to VOO and IVV. After a major revamp in 2020, it now boasts a rock-bottom fee, positioning it as an aggressive competitor.

Here’s a quick look at how they compare:

Metric	SPLG (SPDR)	VOO (Vanguard)	IVV (iShares)
Issuer	State Street	Vanguard	BlackRock
Expense Ratio	0.02%	0.03%	0.03%
Inception Date	Nov 8, 2005	Sep 7, 2010	May 15, 2000
Assets (AUM)	~$85 Billion	~$510 Billion	~$545 Billion
Structure	Open-End ETF	Open-End ETF	Open-End ETF

On paper, SPLG wins on price. It has the lowest expense ratio. But the sticker price isn't the whole story.

The Expense Ratio Battle: Where Basis Points Matter

An ETF's expense ratio gets all the headlines. Here, the competition is brutal—and that’s great for you. For years, VOO and IVV held the line at 0.03%. Then State Street made a move. They dropped SPLG's fee by a single basis point, making it the new low-cost leader.

But does one basis point (0.01%) really matter? On a $10,000 investment, it's the difference between paying $2 or $3 a year. That’s just one dollar. But compounding works on costs, too. Over time, that tiny difference adds up.

Consider a $100,000 investment held for 30 years, assuming a 10% average annual return.

• With a 0.03% ER: Your portfolio grows to approximately $1,724,000.
• With a 0.02% ER: Your portfolio grows to approximately $1,729,000.

That one basis point could mean an extra $5,000 after three decades. It's not a fortune, but it's real money. It’s a clear win for the cheaper fund, assuming all else is equal. Of course, it rarely is.

Beyond the Fee: Uncovering the Total Cost of Ownership

To find the true cost, you have to look deeper. We need to analyze the hidden factors that can help or hurt your returns. This is where the real debate begins.

Tracking Difference: The Real-World Performance Gap

The expense ratio is what you're told you'll pay. The tracking difference is what you actually get. It’s the real-world gap between your fund’s return and the index’s. Sometimes, a well-run fund can even beat its own fee.

How is that possible? One key strategy is securities lending. Fund managers lend stocks like Apple or Microsoft to other institutions and collect a fee. That revenue helps offset the fund's operating costs, lowering the net impact on you.

Vanguard and BlackRock are masters of this game. Their massive scale allows them to generate significant revenue from lending, often making the real cost to investors even lower than the stated fee. State Street is also skilled, but the sheer size of VOO and IVV gives them an edge. In recent years, all three funds have tracked the index with incredible precision. The difference between them often comes down to a statistical rounding error.

Bid-Ask Spread: The Cost of a Single Trade

Every time you trade, you pay the bid-ask spread. It's the tiny gap between the buying and selling price. Think of it as a small transaction fee.

• VOO & IVV: These are two of the most traded funds in the world. Their liquidity is immense. The typical spread is just 0.01%, often a single penny. On a $10,000 trade, that costs you about $1.00.
• SPLG: While very liquid, SPLG trades less often than the two giants. Its spread might be slightly wider, perhaps 0.02% during normal hours. That’s a $2.00 cost on a $10,000 trade.

The Takeaway: If you buy and hold, this difference is almost meaningless. But for active traders or those moving huge sums, the razor-thin spreads of VOO and IVV provide a slight advantage.

Performance Backtest: A 10-Year Horse Race

Theory is great, but results are better. Let's run a hypothetical $10,000 investment over ten years. We'll use the S&P 500's historical average total return of 12.6% as our benchmark and then subtract each fund's fee to see the outcome.

Fund	Initial Investment	Assumed Index CAGR	Net CAGR (After Fees)	Final Portfolio Value (July 11, 2026)	Advantage vs VOO/IVV
S&P 500 Index	$10,000	12.60%	12.60%	$32,746	N/A
SPLG (0.02% ER)	$10,000	12.60%	12.58%	$32,680	+$33
VOO (0.03% ER)	$10,000	12.60%	12.57%	$32,647	$0
IVV (0.03% ER)	$10,000	12.60%	12.57%	$32,647	$0

The numbers don't lie. The lower fee makes a difference, even if it's small. Over ten years, that single basis point would have added $33 to your account. It's not much, but it proves that on cost alone, SPLG has the mathematical edge.

The Deciding Factor? Share Price and Accessibility

For a long time, choosing between VOO and IVV felt like splitting hairs. SPLG changed that. It introduced a practical advantage that might be the single most important factor for many investors: a much lower share price.

With the S&P 500 trading at 7,575.39, the approximate share prices are:

• VOO: ~$700
• IVV: ~$760
• SPLG: $80.00

This is a huge deal. Do you use a brokerage that doesn't offer fractional shares? Are you investing a set amount like $500 each month? If so, SPLG is far more practical.

Imagine you have $500 to invest.

• With VOO or IVV, you can’t afford a single share. Your money would just sit there as uninvested cash, earning nothing.
• With SPLG, you could buy six shares ($480) and put almost all your capital to work instantly.

This means less cash drag. It makes dollar-cost averaging easier. It helps you stay fully invested. For anyone just starting out or investing with smaller amounts, SPLG's low share price is a game-changing advantage.

Frequently Asked Questions About S&P 500 ETFs

As we weigh these options, several common questions naturally arise. Let's address them directly.

Is there a single "best" S&P 500 ETF?

There is no single "best" fund, only the best fund for your specific situation.

• If your primary goal is the absolute lowest advertised fee and you value the accessibility of a lower share price, SPLG is the winner.
• If you are an institutional-level trader or prioritize the absolute deepest liquidity and the tightest trading spreads, VOO and IVV remain the gold standard.
• For most long-term retail investors, the differences are so marginal that any of the three are excellent, world-class choices.

Why not just buy SPY, the original S&P 500 ETF?

SPY (SPDR S&P 500 ETF Trust) is the oldest and most liquid ETF on the planet. However, it was structured as a Unit Investment Trust (UIT), which is less flexible than the open-end ETF structure of SPLG, VOO, and IVV. This structure prevents SPY from reinvesting dividends immediately and makes it less efficient at using securities lending to offset costs. The result is a much higher S&P 500 expense ratio of 0.09% and less favorable tax treatment. SPY is built for high-frequency traders; SPLG, VOO, and IVV are built for long-term investors.

Do these tiny differences in expense ratios really matter?

Yes, absolutely. While the annual difference is small, the principle of minimizing costs is the most reliable way to increase your net returns. Over an investing lifetime of 30-40 years, these basis points compound into thousands, or even tens of thousands, of dollars. Choosing the lowest-cost instrument is a disciplined habit that pays dividends, quite literally, over the long run.

Is it a good idea to own more than one of these ETFs?

No, this would be redundant. Since SPLG, VOO, and IVV all track the exact same 500 stocks in the S&P 500 index, owning more than one offers no diversification benefit. You are simply buying the same assets through a different wrapper. It's far better to choose one and consolidate your investment for simplicity and clarity.

How does SPLG's history affect its reliability?

Some investors may note that SPLG only began tracking the S&P 500 in 2020. Before that, it tracked a different large-cap index. However, this transition should not be a concern. The fund is managed by State Street, the same highly experienced team that manages the nearly trillion-dollar SPY. Their operational expertise in managing index portfolios is beyond question. The "new" SPLG is simply their modern, competitive offering, and its reliability and tracking are on par with its peers. The excellent index fund tax efficiency and low turnover of the S&P 500 strategy remain the same.

The Final Verdict: Ranking the Titans

After a thorough quantitative and qualitative review, we can rank these three excellent funds.

1. SPLG (SPDR Portfolio S&P 500 ETF): For the majority of retail investors in 2026, SPLG emerges as the top choice. It wins on two key fronts: it has the lowest published expense ratio (0.02%), and its highly accessible $80 share price minimizes cash drag and makes dollar-cost averaging far more efficient for those without access to fractional shares.
2. VOO (Vanguard S&P 500 ETF): A very close second. Vanguard's reputation and investor-owned structure are powerful draws. Its performance and total cost are virtually indistinguishable from its peers, and it remains a superb choice. If you are already in the Vanguard ecosystem, there is little reason to switch.
3. IVV (iShares CORE S&P 500 ETF): Another outstanding option that effectively ties with VOO. Its massive scale and institutional adoption speak to its quality. The only reason it falls to third in this specific ranking is the lack of a clear advantage over SPLG's lower fee and more practical share price for the average investor.

Ultimately, the competition in the SPLG vs VOO vs IVV arena has been a spectacular victory for investors. You cannot make a bad choice here. But by focusing on the total picture—fees, tracking, liquidity, and practical usability—SPLG currently presents the most compelling package for building wealth one share at a time.