The unlocking of staked ETH following Ethereum’s upgrade could potentially lead to a sell-off in the market. When staked ETH becomes accessible, some holders might decide to liquidate their positions for profit or to reduce risk exposure. However, the size of this impact depends on the market conditions at the time of the unlock. If Ethereum’s fundamentals remain strong and demand for ETH increases, the effect might be minimal. But in a bearish market, a mass sell-off could significantly impact prices, causing downward pressure.