Institutional flows. Spot ETFs are the best observable proxy for regulated demand; ... September 3, 2026 (@SoSoValue ) was an "all green" day: - BTC: +$731M net inflow (best September day), cumulative ~$55.4B, AUM ~$103B - ETH: +$141M, cumulative ~$13.2B, AUM ~$16B - XRP: +$6.1M, cumulative ~$1.68B, AUM ~$1.55B - SOL: +$6.4M, cumulative ~$1.35B, AUM ~$1.46B September 2 showed the opposite for alts: BTC +$101M while ETH, XRP, and SOL saw outflows. Flows change sign daily, tactical institutional demand, not a permanent one-way bid. Smart money interpretation: BTC remains the liquidity reservoir (IBIT/@BlackRock anchors the complex). ripple:native has the best 2026 persistent accumulation record among alts (~$1.68B since Nov 2025; 13F filings show @GoldmanSachs , #JaneStreet, #Millennium among holders). Real institutional exposure exists, but daily flow is small versus BTC. solana:So11111111111111111111111111111111111111112 has the highest AUM growth rate in the alt group (@Bitwise staking ETF BSOL > $1B AUM), yet the token underperforms over 7 days, wrapper has bids, token remains cyclical high-beta. Stock-to-flow ETF ratios (order of magnitude): - BTC: ~6.3% - ETH: ~5.2% - SOL: ~2.4% - XRP: ~1.7% BTC/ETH are already partially financialized. XRP/SOL still have an absorption gap, more convexity if flows accelerate, more gap risk if they stop.