Teslas stock plunged more than 8% on Tuesday, marking another setback for the electric vehicle giant as it struggles to maintain momentum in 2025. The companys stock hit its lowest level since November, driven by disappointing sales in Europe and growing concerns over CEO Elon Musks controversial political moves. Tesla shares (Nasdaq:TSLA) are now down roughly 25% just this year, making it the weakest performer among the Magnificent 7 stocks, according to Investopedia.The companys valuation also dipped below $1 trillion for the first time in three months, as reported by MarketWatch.Why Tesla shares are down this weekA key factor in Teslas stock slump is a sharp decline in European sales. The companys vehicle sales plummeted 45% across Europe last month, even as overall electric vehicle demand surged, according to the Wall Street Journal. Teslas monthly sales in Germany, for instance, fell 60% year-over-year to 1,277 vehicles, per data from Germanys Motor Transport Authority.Meanwhile, competitors such as Volkswagen, Renault, and SAIC Motor saw increased sales, capitalizing on growing EV interest in countries including Germany, the U.K., and the Netherlands.Musks vocal political involvement in Germanys recent election also may have contributed to Teslas waning. His support for the far-right Alternative for Germany (Afd) party sparked backlash, potentially alienating customers in a key market.Additionally, Teslas Model Y is currently undergoing a refresh, leading some buyers to delay purchases while waiting for the updated model, according to WSJ.Beyond sales figures, Tesla faces growing concerns about its reputation. Some critics have argued that Musks leadership outside of Tesla, particularly his role in running the Trump administrations so-called Department of Government Efficiency (DOGE), is damaging the companys image.On February 15, protestors gathered at Tesla stores and charging stations in cities across the United States to condemn Musks cuts to essential services and mass layoffs related to his work with DOGE.Despite Teslas recent challenges, Europes broader EV market remains strong, with overall electric vehicle sales rising 37.3% last month. Germany, the U.K., and the Netherlands are seeing the biggest gains in sales, according to Yahoo Finance. Whats clear is that Tesla investors are increasingly anxious this week as competitors continue to chip away at its dominance in the industry.