Roger Altman, Evercore founder and senior chairman, warned on Monday that traditional valuation methods struggle to capture high-growth companies such as newly public SpaceX and IPO-bound Anthropic, where enormous scale, artificial intelligence and uncertain long-term cash flows make pricing difficult. "I don’t think anybody understands, at least I don’t, how to value companies like SpaceX or Anthropic," Altman said on CNBC’s "Squawk Box," adding that prices are "very, probably very volatile" and that "people who own them have to be ready for a lot of volatility." Altman pointed to last week’s 8% to 9% drop in chip stocks as a normal correction. SpaceX shares rose more than 7% on Monday after Nasdaq Inc. said the company will join the Nasdaq-100 Index before the market opens on July 7. The stock briefly pushed the company toward a nearly $3 trillion market value, above Microsoft Corp., before retreating. Shares traded about 21% above their $135 IPO price on Monday and were up 8.85% over five days after falling more than 20% last week. The company allocated about 20% of its massive IPO to retail investors globally. Earlier this month, Anthropic confidentially filed to go public; a recent private round valued the company at nearly $965 billion. Anthropic has signed a compute agreement with SpaceX for access to its Colossus data center capacity.