Tesla and Alphabet shares slump in premarket trading as AI spending concerns spook investors

SpaceX, Tesla and X CEO Elon Musk (R) and Google CEO Sundar Pichai attend the presidential inauguration of Donald Trump at the Rotunda of the US Capitol in Washington, on January 20, 2025. Trump takes office for his second non-consecutive term as the 47th president of the United States. Kevin Lamarque | Afp | Getty ImagesShares of Alphabet and Tesla fell in premarket trading on Thursday after both firms signalled increased AI spending, unnerving investors worried about the mounting costs of the artificial intelligence boom. Alphabet shares were around 4% lower, while Tesla's stock fell over 5% in premarket trading.Stock Chart IconStock chart iconAlphabet and Tesla shares this year.Both companies reported negative free cash flow for the second quarter on Wednesday. Alphabet raised its capital expenditure forecast for this year to $195 billion to $205 billion and warned of higher figures in 2027. The Google parent company's previous projection was for capex between $180 billion and $190 billion.Tesla, meanwhile said capex surged 142% year-on-year in the second quarter to $5.79 billion. The company said it expects more than $25 billion in capex this year.Management at both companies l...