Elon Musk's DOGE is considering developing a mobile app for tax filing, per the Washington Post.The news sent shares in tax service providers Intuit and H&R Block tumbling.Elon Musk and Vivek Ramaswamy have been tasked with slashing government spending under Trump.Elon Musk's Department of Government Efficiency reportedly has its first target the US tax system.Musk and Vivek Ramaswamy's cost-cutting agency has discussed developing a mobile app that would let Americans file their taxes for free, two sources told The Washington Post.The news sent the stock prices of H&R Block and Intuit, which sell tax-filing services such as Turbotax, tumbling on Tuesday. Shares were down8%and5%, respectively.The launch of an app would see Musk and Ramaswamy, who have been die-hard supporters of Donald Trump's successful election campaign, follow in the footsteps of Joe Biden.The outgoing president's Inflation Reduction Act introduced Direct File, a free IRS tax-filing system that rolled out in February.The legislation, which attempted to break the stranglehold held by private companies on tax filing, was strongly opposed by Republicans at the time but has been used by over 100,000 taxpayers this year, according to the Treasury.When Trump announced that Musk and Ramaswamy would lead the organization, he said they would be tasked with cutting regulation and government spending "from outside of government," with a deadline of July 2026.Musk and Ramaswamy have suggested they could cut $2 trillion from the federal budget and "delete" entire government departments, although political experts previously told Business Insider that these goals are unrealistic.Since its announcement last week, DOGE has been active on Musk's social media platform, X, with an account for the organization posting that it was seeking to hire "super high-IQ small-government revolutionaries," and Musk proposing an online leaderboard for "the most insanely dumb spending of your tax dollars."Musk and DOGE did not respond to a request for comment from Business Insider, sent outside normal working hours.