I wouldn’t be surprised if Stark Industries does go bankrupt after Tony’s death. It’s main occupation was munitions, which Stark ceased selling. His remaining industries vary in profitability. He could do well in medical devices but those are also heavily regulated with thin margins. Limited pool of people who need fancy exoskeletons. He would have a near monopoly on clean energy sources, which should be massive but realistically isn’t so much. Much of the constant innovative tech keeping the business alive was really spearheaded by Tony Stark.

No shade to Pepper Potts, who I don’t doubt is a fine CEO, but he was Stark Industries just like his dad was. When his stock stayed up it was because of faith in him.

Wayne Enterprise is more like GE. It could have consistently terrible quarters but overall be too big fail. Bruce is also not as crucial, or even a factor, in running the place the way Tony is/was. It would take a major depression or recession to bankrupt it.