According to Glassnode data, altcoin spot trading volume has surged to nearly four times that of Bitcoin, reaching its highest proportion since September 2025. Wintermute stated that its OTC desk's retail clients sold Bitcoin last week to fund this rotation. Meanwhile, US spot Bitcoin ETFs have seen nearly $2.4 billion in inflows over the past five trading days, but daily inflows have steadily declined, from $999 million on September 21 to $134.5 million on September 25. Glassnode noted that as of September 23, 72.5% of the altcoins it tracks have outperformed Bitcoin, up from 39% in August. Glassnode believes that this aggressive burst of risk-taking often coincides with local Bitcoin tops and views it as a historical warning sign. Wintermute added that the breadth of this rotation has reached historical highs, with subsequent market performance being flat or down in over 80% of comparable cases in the following weeks. Macro-wise, the Federal Reserve raised its policy rate to 3.75%-4.00% on September 16, the 10-year US Treasury yield hit 5.23% on September 25, its highest since 2007, and Brent crude oil surpassed $107 on September 28.