The explosion in activity by special purpose acquisition companies, or SPACs, will continue to make it difficult for Berkshire Hathaway Inc. to make deals, Warren Buffett said Saturday at the company’s annual meeting. Rapid deal making by SPACs makes it difficult to find bargains, said Buffett, who said the rise in interest in the vehicles is a function of a mass rush by speculative investors into the markets overall. Buffett quoted economist John Maynard Keynes’s warning about speculative excess: “When the capital development of a country becomes a byproduct of the activities of a casino, the job is likely to be ill-done.” Buffet said Berkshire was “not going to have much luck on an acquisitions while this sort of a period continues…it’s happened before but this is about as extreme” as it’s ever been.

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