U.S. spot Bitcoin and Ethereum exchange-traded funds generated roughly $40 billion in trading volume during the week ended Aug. 16, the highest since the products launched and a sign of deepening institutional participation in digital assets. Ethereum vehicles led the activity. Net inflows into spot Ether ETFs reached about $2.85 billion, their largest weekly haul on record and almost four times the amount that went into comparable Bitcoin products. The surge lifted the group’s assets under management to around $30 billion. Momentum cooled on Aug. 15, when the funds logged a $59.3 million outflow that snapped an eight-day, $3.7 billion winning streak. BlackRock, the world’s biggest asset manager, was a major buyer. Market-tracking data show the firm added roughly $2.32 billion of Ether to its holdings this week—more than double the $887 million it put into Bitcoin. BlackRock’s Bitcoin ETF now controls about 749,000 BTC, a stake worth roughly $85 billion at current prices, while its Ether ETF briefly ranked as the most-traded U.S. ETF of any type on Aug. 15. Bitcoin ETFs also felt the week’s turbulence, reporting a $14.1 million daily outflow on Aug. 15 that ended a seven-day inflow streak. Even so, the combined record trading volumes underscore sustained institutional demand for both of the largest cryptocurrencies, despite episodic profit-taking and price swings.