Horizon Small/Mid Cap Core Equity ETF (SMOX)

The Horizon Small/Mid Cap Core Equity ETF (SMOX) holds several hundred US small-cap and mid-cap companies using a fundamentally weighted index approach: instead of weighting stocks by market capitalization—the way most index funds do—it weights them by fundamental measures like sales, earnings, and book value. The effect is a tilt toward cheaper valuations and away from the most expensive and crowded names within the small and mid-cap universe.

Most index funds are market-cap weighted. The S&P 500, the NASDAQ 100, even most SMID indexes weight companies by their market price, so bigger companies exert larger pulls on the index. There is elegance in that simplicity: the market votes with real dollars, so the index reflects actual investor consensus. But market-cap weighting has a flaw that has troubled investors for decades: it automatically overweights the most expensive stocks and underweights the cheapest, the opposite of classic value-investing discipline. A stock that has soared to an astronomical price-to-earnings ratio gets a larger index weight, while a beaten-down firm trading below book value gets a smaller one. Fundamental-weighting flips that logic.

SMOX’s index construction pulls the weight from price and anchors it to underlying business metrics. A company’s index weight is based on its sales, earnings, or book value rather than its stock price. As a result, SMOX naturally gravitates toward cheaper valuations and underweights momentum-driven runups. When a bubble inflates and money rushes into the most expensive stocks, SMOX’s constituents get lighter. When a panic deflates valuations across the board, SMOX’s holdings become relatively more valuable.

The mechanics and philosophy of fundamental weighting

Fundamental weighting is not new, but it was brought into the mainstream by Research Affiliates, a firm that developed systematic indexes around this idea and licensed them to multiple ETF sponsors. Horizon Investments (now part of Invesco) is one of those sponsors. The methodology is straightforward: take a large universe—all US small and mid-cap stocks above certain size thresholds—calculate fundamental metrics (sales, earnings, book value, sometimes cash flow), assign weights based on those metrics, and rebalance periodically as companies grow and shrink.

The philosophical claim is that fundamental weighting is more rational than market-cap weighting. Market prices reflect emotion, short-term flows, and herd behavior as much as underlying value. A company with stable, growing sales might trade cheaply while a momentum stock with collapsing profitability trades dear. A fundamental index corrects for that disconnect: it owns the former and underweights the latter. Over decades, if mean reversion holds and if prices eventually reflect fundamentals, a fundamental-weighted index should outperform a market-cap-weighted index.

What does this mean in practice for small-cap investors?

Small and mid-cap stocks are fertile ground for fundamental-weighting strategies. The small-cap universe is less efficiently priced than large-cap stocks; individual stocks can drift away from fundamental value for years. A small regional manufacturer or specialty retailer might be unloved while the market chases technology stocks, creating a discount from fundamental value. Fundamental weighting identifies and owns those positions, profiting when the market eventually recognizes their worth.

SMOX will hold dozens of small and mid-cap companies across all sectors: industrials, materials, financials, health care, consumer discretionary, and others. The portfolio will naturally lean toward value (cheaper metrics relative to price) and away from growth (expensive multiples). In a bull market driven by technology and growth momentum, that tilt will be a drag. In a bear market or a rotation toward value, the tilt will shine.

The fund’s tilt is not extreme. It is not a pure small-cap value fund; it is more a core small/mid-cap that happens to have a modest value lean built into its weighting. A researcher comparing SMOX to a market-cap-weighted SMID index will see meaningful but not night-and-day differences in sector tilts and valuation profiles.

Costs, rebalancing, and tax efficiency

Fundamental-weighted indexes rebalance frequently—often quarterly or semi-annually—because as stocks trade and prices move, the fundamental weightings drift. A stock whose sales have grown will need more weight; one whose earnings have fallen needs less. That rebalancing incurs trading costs and can generate capital gains. The expense ratio of SMOX reflects these rebalance costs, typically a moderate level for a factor-tilted index fund, higher than plain market-cap index funds but lower than active management.

The rebalancing itself generates tax consequences for taxable accounts. A fundamental-weighted fund will turn over its holdings more frequently than a passive cap-weighted index, realizing gains and losses. For tax-advantaged accounts (IRAs, 401ks), this is irrelevant. For taxable investing, it is a real cost to model, especially over decades.

The ETF structure itself is efficient. Because SMOX trades on an exchange, the creation/redemption mechanism ensures the NAV stays in line with the underlying holdings’ value. There is no discount or premium risk that plagues some closed-end funds.

The real risks and unanswered questions

The core bet—that fundamental weighting outperforms market-cap weighting—is not yet settled by history. Fundamental-weighted indexes have been around in their modern form for fewer than twenty years, so the long-term track record is short. In that period, they have had years of outperformance and years of underperformance depending on whether value or growth was winning. A researcher should backtest SMOX’s historical returns against a market-cap-weighted SMID index to see if the premium exists and how volatile it is.

A second risk is that the small-cap universe itself is volatile. Small companies have fewer resources to weather economic storms, and SMOX is not a defensive or low-volatility product. It will own profitable small companies, but they will still gyrate more than a large-cap core fund would. An investor expecting SMOX to be stable is misaligned with what they own.

A third risk is concentration and liquidity. Small-cap stocks, as a group, are less liquid than large-cap stocks. Individual positions in SMOX will vary in tradability. In a market panic, when you might want to sell, small-cap liquidity can dry up fast, and the fund’s price can diverge from its NAV for brief periods. This is not unique to SMOX, but it is a real constraint for large positions or risk-averse investors.

Finally, there is the risk that the value tilt does not pay off. Value investing has been out of favor for years, as growth has dominated returns. If that regime persists, a value-leaning fund like SMOX will lag. No one can predict whether growth or value will win next year or the next decade. Investors in SMOX need to be comfortable holding through extended periods of underperformance relative to growth-heavy benchmarks.

Researching SMOX and deciding if it fits

Start with Horizon’s factsheet, which lays out the index construction, rebalance frequency, and current sector and valuation profile. Pull the last three to five years of returns compared to a plain SMID market-cap index (like VBR or IJH). Look for periods where fundamental weighting lagged (these happen) and periods where it led (these also happen). Ask yourself whether you have a higher conviction that the current era of value underperformance will reverse.

Read the prospectus to understand the exact fundamental metrics used and the weighting scheme. Some fundamental indexes use equal weight, equal-weighting to metrics and re-rank frequently. Others use fixed-weight blends and rebalance less often. The mechanics matter for how volatile the portfolio is.

Check the fund’s tax-efficiency metrics—the annual turnover rate and the percentage of holdings that were changed in the last year. If you are investing in a taxable account, a high-turnover fundamental index can be more costly than it appears.

SMOX works best for an investor who believes in the small-cap premium (that smaller companies outperform over decades), who is comfortable with value-style volatility, and who is willing to hold through extended periods where growth outpaces value. It is not a tactical bet; it is a long-term structural tilt. And it is best suited for an account where tax efficiency is not a paramount concern—an IRA or 401k, rather than a large taxable position with a long time horizon.