U.S. spot bitcoin ETFs took in $606 million on Aug. 20, up from $517 million the day before, while ether ETFs pulled in $221 million, per SoSoValue data. Every listed asset drew inflows, with XRP funds adding $13 million and Solana $15 million, a second straight day of accelerating institutional buying behind bitcoin's breakout.The flows answer the question hanging over the run. Bitcoin cleared $69,000 on Wednesday and pushed above $72,000 on Thursday, and the worry was whether the move was real demand or shorts getting squeezed. Two days of inflows this size, each bigger than the last, point to institutions chasing the break rather than a one-day liquidation spike doing all the work.Bitcoin traded near $75,500 on Friday after touching $72,344 on Thursday, holding most of the week's gains.The near-term risk is the pace. Bitcoin has run from below $64,000 to above $72,000 in three days, and rallies that steep tend to give back ground once the momentum cools. The flows are the thing to watch. If ETF buying holds into next week, the breakout has a foundation. If it fades, the move looks more like a spike than a trend.