FILE / VOO-SPLG
2026 edition
CROSS-ISSUER S&P 500 ETF PAIR
VOO vs SPLG: same 500 stocks, two ETF issuers
Vanguard's VOO and SPDR's SPLG both track the S&P 500. SPLG charges one basis point less. VOO is dramatically more liquid. The choice comes down to whether you trade large blocks or set-and-forget.
QUICK VERDICT
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VOO is the right default for most retail investors. The 1 basis-point fee gap versus SPLG is recovered many times over by VOO's tighter bid-ask spreads on any sale of meaningful size. Vanguard's mutual fund counterpart VFIAX gives a tax-free cross-share-class path inside Vanguard.
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SPLG only if you are deliberately optimising the headline expense ratio (0.02 versus 0.03 percent), you trade in small whole-share lots where the lower share price helps clean contributions, and you are confident the slightly wider spread will not eat the savings on entry and exit.
Both ETFs deliver the S&P 500. VOO ships at 0.03 percent per the Vanguard VOO product page. SPLG ships at 0.02 percent per the State Street SPLG product page. The 1 basis-point difference is real but small. Liquidity, share price, and ecosystem effects matter more for most investors.
Both funds replicate the same S&P 500 index from S&P Dow Jones Indices. Tracking error over a year is typically less than 0.05 percentage points for both.
FIG. A / SPEC SHEET
Side by side
SECTION 02 / WHY 1 BASIS POINT IS NOT THE ANSWER
The headline expense gap is real but tiny
On a $100,000 balance, the difference between 0.02 percent and 0.03 percent is $10 per year. Over thirty years compounding, that grows to roughly $700 of foregone wealth on a $100,000 starting balance assuming a 7 percent real return. Real, but small relative to the variables you actually control: contribution rate, asset allocation, behavioural discipline.
What can offset that 1 basis-point edge: bid-ask spread crossings. If you trade a $50,000 block of SPLG at a $0.02 spread versus a $0.01 spread on VOO, you have given back $14 of transaction cost on entry and another $14 on exit. That round trip more than wipes out a year of fee savings. For active traders or anyone executing large lump sums, VOO's tighter spread compounds in the right direction.
For pure dollar-cost averaging into a buy-and-hold position with no expected sales for decades, SPLG's 1 basis-point edge mathematically wins by a small margin. For everyone else (which is most retail investors), VOO's liquidity advantage matters more.
SECTION 03 / THE SPDR FAMILY ECOSYSTEM
SPLG sits inside the SPDR Portfolio cheap-fee push
SPDR (State Street Global Advisors) launched the original S&P 500 ETF (SPY) in 1993, still the largest ETF by AUM. SPY charges 0.0945 percent, expensive by modern standards. To compete with VOO and IVV in the cheapest-S&P-500 segment, State Street launched SPLG in 2005 and aggressively cut its expense ratio over the years to the current 0.02 percent.
SPLG belongs to the SPDR Portfolio family which includes SPTM (total market), SPMD (mid-cap), SPSM (small-cap), SPDW (developed ex-US), SPEM (emerging markets), and SPAB (aggregate bond). All run at 0.03 percent or 0.02 percent. If you want a multi-fund portfolio entirely from the SPDR Portfolio lineup, this is the cohesive option. Most Bogleheads-style portfolios mix Vanguard and iShares for fund-level robustness rather than committing to a single issuer.
For comparison, the Vanguard equivalents in the same lineup are VTI (total market), VO (mid-cap), VB (small-cap), VEA (developed ex-US), VWO (emerging markets), and BND (aggregate bond). The Vanguard side is more widely held and more frequently the default in retail-investor recommendations.
SECTION 04 / WHEN SPLG SHARE PRICE HELPS
Whole-share contributions and custodial accounts
VOO trades around $520 per share as of 2026. SPLG trades around $70. If you contribute $200 a month and your brokerage does not support fractional ETF purchases, you can buy 2 full shares of SPLG for $140 with $60 of cash drag, but only 0 shares of VOO with the entire $200 sitting in cash for the month.
Most major US brokerages now support fractional ETF purchases (Fidelity, Schwab, Robinhood, M1, Public, SoFi). Where this is not yet the case: many custodial UTMA/UGMA accounts, some 401(k) plan brokerage windows, some workplace ESPP-linked brokerages, some smaller regional brokerages. In those contexts, SPLG's lower share price is a real practical benefit.
For a Vanguard customer, the cleaner solution to the share-price problem is to use VFIAX (the mutual fund counterpart to VOO) which lets you contribute exact dollar amounts. VFIAX requires a $3,000 minimum and is Vanguard-only. See the VOO versus VFIAX page for the same-issuer wrapper analysis.
DESK Q&A
Frequently asked
Q01Is SPLG actually cheaper than VOO?
On expense ratio, yes: 0.02 percent versus 0.03 percent per the issuer-published prospectuses. On total cost (expense + bid-ask spread + tracking error), it depends on trade size and frequency. For buy-and-hold with no sales, SPLG mathematically wins by a tiny margin. For any execution of meaningful size, VOO's tighter spread can give back the savings.
Q02Does SPLG have a mutual fund version?
No. State Street's mutual fund offerings do not include an S&P 500 mutual fund equivalent to SPLG. If you want a mutual fund version of an S&P 500 fund, the choices are VFIAX (Vanguard, $3,000 minimum, 0.04 percent), FXAIX (Fidelity, $0 minimum, ~0.015 percent), or SWPPX (Schwab, $0 minimum, ~0.02 percent). See the IVV versus FXAIX page for the cheapest-S&P-500-fund comparison.
Q03Why is VOO so much more liquid than SPLG?
VOO is one of the three biggest ETFs in the world by AUM ($700 billion-plus) and one of the most-traded by daily volume. The depth attracts more buyers and sellers, which tightens spreads, which attracts more buyers and sellers. SPLG at $70 billion-plus is large in absolute terms but ten times smaller than VOO. The relative liquidity gap is unlikely to close because VOO's first-mover advantage in the cheap-S&P-500 ETF segment is now self-reinforcing.
Q04Should I switch from SPY to SPLG?
If you hold SPY in a tax-advantaged account, switching to SPLG (or VOO or IVV) saves you 7 to 8 basis points per year on expense ratio. SPY at 0.0945 percent makes sense only for institutional traders who want the deepest-possible options market and the highest-volume tradeable. In a taxable account, switching realises any embedded capital gain on SPY. Run the math on your specific cost basis before switching.
Q05Is there a tax difference between VOO and SPLG?
Not meaningfully. Both use the standard ETF in-kind creation and redemption mechanism that flushes appreciated low-basis stock to authorised participants without realising taxable gains for shareholders. Per their issuer-filed annual reports on SEC EDGAR, both have distributed near-zero long-term capital gains in most recent years. Dividends are equally qualified under IRS Topic 404.
Q06Can I tax-loss harvest between VOO and SPLG?
Probably yes, though the IRS has not formally ruled on whether two S&P 500 ETFs with different issuers count as substantially identical for wash-sale purposes. Most tax practitioners treat them as similar-but-not-identical (different funds, different issuers, technically different securities). Some practitioners pair VOO with SPY or IVV instead to be safe. Consult a CPA for your specific tax situation.
DESK ROUTING
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