SPMO vs VOO: Which Is the Better Pick in 2026?

Overview

SPMO and VOO are both S&P 500–tracking ETFs, but they pursue fundamentally different exposures within that index. VOO holds all 500 constituents in market-weight proportions—true broad-market S&P 500 exposure. SPMO screens the same 500 names for momentum characteristics, concentrating its portfolio in the highest-momentum stocks while excluding or underweighting slower performers. The result: SPMO tilts toward a performance-chasing factor strategy, while VOO delivers cap-weighted index purity.

How they differ

The defining difference is portfolio construction. VOO mirrors the S&P 500's market-cap weighting, holding all 500 stocks. SPMO applies momentum scoring to those same 500 and weights them by momentum rank, meaning its top holdings look nothing like the index—it's overweight the market's strongest performers and underweight or absent the laggards. This structural choice explains why SPMO's beta is 1.29 versus VOO's 1.0: SPMO amplifies market moves because momentum stocks tend to move faster than the broad market.

The expense ratio gap favors VOO sharply. VOO charges 0.03% while SPMO charges 0.13%—a 0.10 percentage point spread that compounds over decades. VOO's $1033B in AUM dwarfs SPMO's $20.3B, reflecting both its earlier inception (2010 vs. 2015) and its appeal as the default S&P 500 core holding. On yield, VOO edges ahead at 1.15% versus SPMO's 0.65%, a natural consequence of VOO's market-weight approach (slower-growth stocks typically pay higher dividends than momentum leaders).

Who each is best for

SPMO: Fits investors seeking explicit factor tilting within large-cap U.S. equity—those who believe momentum as a quantitative signal can enhance returns enough to justify tracking error relative to the cap-weighted index, and who have conviction that current market leaders will sustain outperformance.

VOO: Fits investors pursuing core U.S. large-cap exposure with minimal cost and maximum simplicity—those indifferent to tactical factor bets and comfortable with the market's natural weighting, including both high-flyers and cyclical laggards.

Key risks to know

• Momentum factor mean reversion. Momentum has exhibited long performance plateaus followed by sharp reversals. SPMO's structural overweight to the recent winners creates drawdown risk if the market rotates away from those names—a risk that neither index funds nor factor funds can eliminate, but momentum funds cannot diversify away.

• Concentration relative to cap-weight. By construction, SPMO's top holdings represent a much larger portfolio share than they do in VOO. Market concentration in a handful of mega-cap tech and growth names is a broad-market risk, but SPMO's momentum tilt could amplify it during periods when the index's biggest gainers cluster in a single sector.

• Tracking error and cost leakage. SPMO's 0.10 percentage point cost disadvantage versus VOO translates to roughly 10 basis points of annual underperformance before any factor alpha materializes. For momentum to outperform on an after-cost basis over a full market cycle, the factor signal must overcome both the fee gap and inevitable periods of underperformance.

• Higher volatility in down markets. SPMO's beta of 1.29 means it is more likely to decline faster than the broad market during selloffs, particularly when momentum reversals coincide with equity downturns—a scenario where factor funds typically face simultaneous headwinds from both market decline and factor derating.

Bottom line

VOO serves as the lower-cost, lower-complexity core S&P 500 holding; SPMO bets that momentum-driven concentration can offset its 0.10% cost disadvantage and higher volatility over the long haul. If your goal is index-matching simplicity with minimal drag, the math favors VOO's 0.03% expense ratio and market-weight structure. If you hold conviction that momentum as a factor offers return potential sufficient to justify tracking error and cost, SPMO's discipline toward that signal may align with your allocation philosophy—though factor performance is cyclical and never guaranteed. Past performance doesn't predict future results.