21Shares has applied for a spot exchange-traded fund based on Dogecoin (DOGE) in the US, backed by the House of Doge.The partnership aims to bring transparent and institutional-grade investment options for Dogecoin to the market.Dogecoin, with a market cap of $22.9 billion, is the eighth biggest cryptocurrency.21Shares joins Bitwise and Grayscale in the race to offer Dogecoin-based investment products in the United States.