Last week in M&A was the best that 2023 has had to offer thus far. Wachtell, Lipton, Rosen & Katz and Sullivan & Cromwell led a $43 billion biotech deal, while Latham & Watkins, Shearman & Sterling and Freshfields, Bruckhaus & Derringer steered a $12.5 billion software deal.

That should be good news for the deal world, but some fresh dark clouds—first appearing in the form of an old-fashioned bank panic—could ultimately lead to rain on the parade.