Altcoin exchange-traded funds (ETFs) in the U.S. are encountering significant structural limitations that hinder their growth compared to Bitcoin ETFs, according to recent analysis by financial institutions. While investor interest in diversified cryptocurrency exposure is rising, altcoin ETFs struggle with supply constraints and scalability issues. Unlike Bitcoin ETFs, which hold about 7% of Bitcoin's circulating supply, altcoin funds find it challenging to accumulate substantial portions of their underlying assets due to market fragmentation and varying fundamentals. The cryptocurrency market's structure presents additional hurdles for altcoin ETFs. Bitcoin's established market position and institutional recognition provide it with clearer regulatory frameworks and broader acceptance. In contrast, altcoin markets are fragmented across numerous projects, leading to heightened sensitivity to market trends and volatility challenges for fund managers. Despite these challenges, long-term investor interest in altcoin ETFs continues to grow. The broader cryptocurrency ETF landscape remains in its early stages, with over 40 crypto ETFs launched this year, yet their market share in the U.S. ETF sector remains minimal. As corporations increasingly explore digital asset strategies, the potential for growth in the altcoin ETF sector exists, but it is likely to follow a different trajectory than Bitcoin ETFs due to structural differences and regulatory complexities.