Altcoins outperform in thin markets as bitcoin stays below $83,500 and ETF outflows mount

Smaller cryptocurrencies led the market higher on Monday even as bitcoin stayed below $83,500 and institutional flows remained weak. The CoinDesk 80 rose about 3% over 24 hours, more than twice the 1.2% gain in the CoinDesk 5, showing stronger momentum in smaller tokens than in the largest assets. CoinDesk research said bitcoin and ether order-book depth has recovered to pre-crash levels since the Oct. 10, 2025 flash crash, while altcoin liquidity has kept thinning, leaving price moves more exposed to shallow market conditions. At the same time, U.S.-listed spot bitcoin ETFs posted $681 million in net outflows last week, the largest weekly withdrawal since June, according to SoSoValue. Spot ether ETFs have not recorded a single day of inflows since Sept. 28, extending their outflow streak to nine days, also the longest since June. In derivatives, trading volume jumped to $126 billion in 24 hours, up 81%, but open interest rose only 2.44% to $145.8 billion, pointing to heavy turnover rather than broad new leverage. CoinDesk also highlighted notable positioning in ZEC, NEAR, STRK and ZRO, while options activity on Deribit showed continued demand for downside protection in bitcoin.