Fidelity's FBTC led a surge in capital into spot Bitcoin ETFs with $311 million on Sept. 18, with BlackRock's IBIT adding another $108 million. Total daily net inflows for the Bitcoin category reached $433 million, and Ethereum's spot products drew $144 million in the same window. BlackRock's ETHA recorded $114 million of that total, while Fidelity's FETH contributed $26.2 million.

Other spot crypto products failed to attract similar interest during the same trading day. Solana ETFs remained flat with no net movement, and XRP products recorded a small outflow of $43,000. These results indicate a concentration of institutional demand in the two largest digital assets compared to smaller competitors.