Altcoin open interest has surged to $38.9 billion, surpassing Ethereum's $29.4 billion and approaching Bitcoin's $40.5 billion, according to CoinMarketCap. This increase comes as traders anticipate the Federal Reserve's interest rate decision on Wednesday, which could influence market dynamics. Data from Coinalyze underscores the growing investment in altcoins as market participants brace for potential shifts driven by the Fed's monetary policy actions.