Digital assets behemoth Grayscale has filed for a spot Solana (SOL) ETF, converting its existing Solana Trust (GSOL).Grayscale's filing reflects growing institutional confidence in Solana, following the success of Bitcoin (BTC) and Ethereum (ETH) ETFs.If approved, the Grayscale Solana Trust would trade on the NYSE under the ticker GSOL, improving investor access to SOL.Grayscale is the fifth asset manager to apply for a spot SOL ETF, with the price of SOL surging after the filing.