On May 18, 2026, the U.S. cryptocurrency asset spot ETF experienced a rare large capital outflow in a single day this year: according to cross-statistics from multiple data platforms, the total net outflow of Bitcoin spot ETFs in the United States that day was approximately $648–649 million, with BlackRock’s IBIT seeing a net outflow of about $448 million, making it the product with the largest capital outflow that day. At the same time, the Ethereum spot ETF in the U.S. recorded a total net outflow of about $86.4 million. It is important to emphasize that IBIT had a historical cumulative net inflow of approximately $65.333 billion prior to this, and this large redemption seems more like a concentrated reflection of long-term funds reducing leverage or adjusting positions in an environment where macro and geopolitical uncertainties still exist, coupled with the simultaneous redemption of both Bitcoin and Ethereum spot ETFs. This combination signal is seen by some investors as an early indication of a shift towards a more cautious risk appetite, while whether this will evolve into a longer-term change in capital direction remains to be validated by subsequent trading day data.

IBIT sees a net outflow of $448 million in one day: even the leader is reducing positions

In the context of the collective net outflow of Bitcoin spot ETFs, BlackRock's IBIT, regarded as one of the most concentrated Bitcoin spot ETFs in the U.S. market, is the “main force of capital withdrawal.” According to public data, on May 18, 2026, the overall net outflow of U.S. Bitcoin spot ETFs was approximately $648–649 million, with IBIT’s net outflow being about $448 million, accounting for nearly 70%, while other products such as Fidelity FBTC, Bitwise BITB, and Invesco BTCO contributed significantly less to the outflow. This indicates that the marginal selling that day mainly came from the leading product's own position reduction. Considering that IBIT had a historical cumulative net inflow of approximately $65.333 billion, this $448 million redemption only corresponds to a small percentage of its long-term net inflow volume. Judging from the absolute position scale, long-term bullish configurations have not been fundamentally shaken, but it clearly reflects that even “the product with the most concentrated long-term funds” is using the ETF redemption mechanism for stage-wise position reduction and risk exposure adjustment.

Sympathetic outflows of Bitcoin and Ethereum ETFs on the same day

From a sector perspective, the outflow on May 18 was not limited to IBIT. Excluding the net outflow of approximately $448 million from IBIT, public data indicates that Fidelity FBTC saw a net outflow of about $63.4 million that day, Bitwise’s BITB had a net outflow of about $9.2 million, and according to a single channel's statistics, Invesco BTCO also recorded a net outflow of about $3.8 million. In the total net outflow of approximately $648–649 million from the U.S. Bitcoin spot ETFs that day, while IBIT contributed the majority, multiple products simultaneously shifted to net redemption, indicating that capital adjustment has spread from a single product to a collective behavior across the entire Bitcoin ETF sector.

Notably, on the same trading day, the U.S. Ethereum spot ETFs also showed a total net outflow of about $86.4 million (different sources have slight discrepancies in the exact values), indicating that both Bitcoin and Ethereum products faced simultaneous pressure. Since such spot ETFs typically hold Bitcoin or Ethereum on-chain through custodians, but relevant parties have not disclosed corresponding specific addresses and transaction paths, external observers can only see the redemption results at the product level. Some market opinions interpret this cross-asset “concurrent net outflow” as a signal of a temporary decline in traditional fund risk appetite, but in the absence of longer-term data and on-chain detailed verification, this judgment remains a cautious interpretation of the day’s resonance phenomenon.

Traditional funds are currently shifting to a more cautious stance

From a timeline perspective, U.S. Bitcoin spot ETFs experienced a prolonged period of sustained net inflow after receiving approval at the beginning of 2024, with BlackRock's IBIT accumulating a net inflow of approximately $65.333 billion, reflecting that traditional funds were initially more inclined to “one-sidedly increase positions.” Entering late 2025 and early 2026, this rhythm began to change, as Bitcoin and Ethereum spot ETFs frequently showed stage-wise single-day net outflows, with the simultaneous withdrawals of approximately $648–649 million from Bitcoin and about $86.4 million from Ethereum on May 18 serving as a concentrated manifestation of this change in data.

In terms of motivation, some market commentary speculates that the current multi-day net outflows might be related to some investors choosing to realize profits at high points following prior accumulated gains or actively reducing exposure to cryptocurrency assets in an environment with macro and geopolitical uncertainties, but these are all based on phenomena rather than conclusions directly supported by on-chain or quantitative data. Existing public data does not provide a one-to-one correspondence relationship between consecutive net outflow days, cumulative scales, and specific external events, nor is it easy to track changes in on-chain addresses at the custody level. Therefore, a more prudent statement is that traditional fund risk appetite compared to the earlier stage of continuous subscriptions indeed appears more volatile and cautious, but whether this constitutes a long-term trend still requires further verification by subsequent data.

How ETF creations and redemptions are transmitted to on-chain positions

Mechanistically, the Bitcoin and Ethereum spot ETFs correspond to on-chain spot positions under custodial institutions, and these assets are concentrated in cold wallets or custodial accounts. When share subscriptions increase, the ETF needs to increase its underlying spot exposure; custodians either receive additional Bitcoin or Ethereum and deposit them in custodial wallets, or cover the required positions through market transactions. Conversely, during periods of net redemptions, custodians theoretically need to simultaneously reduce their spot positions or adjust hedge positions to keep the on-chain custodial scale matched with ETF share changes. Therefore, when there is a concentrated net outflow on a certain trading day, the market naturally associates it with potential position reductions or tightening risk appetite at the custodial level, thus amplifying attention to price and volatility emotionally.

Specifically regarding May 18, 2026, the net inflow scale of Bitcoin and Ethereum spot ETFs can be clearly quantified at the product level, but custodians have not disclosed the corresponding on-chain addresses and transaction paths, and current public on-chain data is difficult to map directly to a single ETF product. This means we cannot accurately quantify how much Bitcoin or Ethereum was actually sold, transferred, or simply absorbed through internal hedging on-chain that day, and relevant analysis tends to remain on the structural assumption of "custodians needing to rebalance spot and risk positions," rather than making quantitative judgments on the on-chain impact of this event based on verifiable address-level evidence.

The next stop for crypto ETFs after the storm

Path-wise, the simultaneous large net outflows of approximately $648–649 million from Bitcoin spot ETFs and about $86.4 million from Ethereum spot ETFs on May 18, 2026, is a rare "Bitcoin + Ethereum" simultaneous withdrawal event since the product was approved in early 2024, constituting a temporary emotional shock to this asset class and symbolizing a transition from the early one-sided net subscription phase to a new phase where inflows and outflows are more frequent and the rhythm more complex. However, it is necessary to acknowledge that after IBIT recorded a net outflow of approximately $448 million that day, its historical cumulative net inflow remained about $65.333 billion, and the substantial stockpile of funds accumulated by U.S. Bitcoin spot ETFs from 2024 to 2025 has not been overall reversed, making this more like a pressure test in the context of macro uncertainty rather than a validated long-term inflection point. What is worth tracking next is whether the net subscriptions and net redemption rhythms of Bitcoin and Ethereum spot ETFs show directional shifts in the coming weeks, whether the price elasticity of Bitcoin and Ethereum spot against capital inflows and outflows changes, and how these market reactions correlate with external variables such as macro rates and risk appetite. For investors, regarding the data from May 18 as an important sample for observing traditional fund attitudes is valuable, but a single-day net outflow itself is insufficient to support clear medium- and long-term judgments. ETF fund data should be comprehensively assessed in the context of price behavior, macro environment, on-chain structure, and other dimensions, rather than being isolated as the sole trading basis or established trend signal.

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