The U.S. ETF market is getting crowded, and issuers are hunting for ways to stand out. Their latest move? Loading up on private companies. What used to be a niche offering is now turning into a full-blown marketing strategy, especially as investors chase growth opportunities during what's been a long dry spell for IPOs.

Private Names Are the New Shiny Object

A growing number of ETFs now offer indirect exposure to high-profile private companies through secondary-market investments or crossover strategies. Take the ERShares Private-Public Crossover ETF (XOVR), which grabbed headlines for its SpaceX position. Late last year, the fund saw a surge in assets as SpaceX IPO rumors heated up, according to Bloomberg. It's a perfect example of how a recognizable private name can drive serious investor interest.

Now, actively managed ETFs are doubling down on this approach. The Baron First Principles ETF (RONB) has gone even further, taking sizable positions in private companies like SpaceX and xAI alongside public holdings such as Tesla, Inc. (TSLA).

These allocations aren't just about offering something different. They also signal a shift toward more concentrated portfolio construction, which brings its own set of challenges.

The Valuation and Liquidity Problem

Here's where things get tricky. Private companies don't trade publicly, so there's no continuous price discovery. Instead, their values come from fair value models that typically reflect sporadic market transactions. That means the valuations sitting in your daily-traded ETF might not reflect what those assets would actually fetch if you tried to sell them today, as Etf.com pointed out.

Liquidity adds another wrinkle. When an ETF sees inflows, managers can't just go out and buy more of their private holdings immediately. That dilutes the private exposure. But when redemptions hit, managers typically sell the public holdings first because they're easier to liquidate. The result? The private assets become a bigger slice of what's left, cranking up concentration risk for remaining investors.

The Industry's Balancing Act

This isn't a problem isolated to one or two funds. As more ETFs lean on private company exposure to carve out a niche, industry watchers are sounding the alarm that investors might not fully appreciate the concentration and liquidity risks baked into these strategies.

For issuers, private exposure is a smart way to differentiate in a saturated market. For investors, the trade-off is a more complicated risk profile that could become painfully obvious when markets get volatile.