Grayscale Investments has filed for its sixth altcoin exchange-traded fund (ETF) focused on Hedera (HBAR).The filing aims to list and trade a Hedera ETF, allowing investors to gain exposure to HBAR without holding the asset directly.The SEC will review the filing for up to 240 days before making a decision, which will be closely watched by investors and industry stakeholders.Grayscale has been actively expanding its range of cryptocurrency ETFs, with filings for Solana, Polkadot, Dogecoin, XRP, and Cardano.