YieldFi's yUSD, with a current market cap of $158 million, is facing liquidity concerns as its largest position is held in the ABRC Morpho Vault, according to analyst Togbe. The primary supply position is in the yUSD/USDC market, with borrowers leveraging yUSD in Morpho and Euler markets. The second-largest position is a negative-yielding mHYPER position, with YieldFi accounting for over 10% of mHYPER's total value locked (TVL). On Arbitrum, mHYPER lends against yUSD, while the second-largest allocation is Stream Finance's xUSD. Togbe highlights a chain of circular lending supporting multiple yield vault markets, warning that if yUSD cannot fully redeem deposits, mHYPER users could face lending losses. Notably, during the October 11 event, yUSD experienced a $50 million outflow.