Berkshire Hathaway shares have fallen 15% from their May record, sliding to a six-month low on Monday after the conglomerate issued what was described as a "dire" warning about the impact of U.S. tariffs on its businesses. The drop comes even as many U.S. companies celebrate the cash windfall from President Donald Trump’s tax overhaul, underscoring investor unease that higher import duties could offset those gains. Commentators noted that roughly one-third of Berkshire’s assets remain in cash and Treasury bills, giving Warren Buffett significant firepower should market valuations retreat further. Barron’s compared the share-price weakness to the late-1990s stretch that preceded Berkshire’s strong outperformance during the 2000 dot-com bust. Despite the pullback, Berkshire has been selectively putting money to work, increasing its stake in satellite-radio operator Sirius XM to 37% after the broadcaster’s earnings-driven sell-off, according to Marketsday. The company also continues to hold roughly 300 million Apple shares, although market observers say the position may have been trimmed in recent months. The combination of tariff uncertainty, a swollen cash pile and opportunistic stock purchases is fuelling debate over whether Buffett is positioning Berkshire for another period of outperformance once current market exuberance cools.