Because the bar is really high if they’re a news outlet. You have to prove that they knew what they were saying was false, and did it with the intent to harm.

Besides, I’m sure SuperMicro just wants it to blow over and be done with it. Being in the news for a lawsuit will bring it up again and possibly harm them financially as people (managers who order) who don’t understand things have knee jerk reactions.

Being in the news several more times for a case about "spy chips" in your hardware isn't worth any money they'd get?

Large commercial lawsuits are like investment, you invest precious resources into a lawsuit that may or may not pay off.

It's entirely reasonable for a company to decide that it's not worth the investment and not pursue.

And to refer back to this article, it's the French AMF fined Bloomberg, Vinci only had to file a complaint, not a full lawsuit with teams of lawyers.

If Super Micro knows they didn’t do it, they should absolutely love the story. Buyback the underpriced shares and make a ton of free money once the market realized the Bloomberg story is false. I don’t know if they actually did that, but that’s what I would have done. I didn’t actually do that because I trusted Bloomberg a lot. But there was substantial profit to be made as an insider. I bet many/most employees made that trade, at the very least.

Generally, when a company doesn't sue over something like this, it's because they don't have a case. And that always means that enough of the allegations are true that they couldn't win an absolutely massive judgement in court.

Because in the US, truth is an absolute defense to the defamation torts. (The same is not truth in the UK; you can still be liable for defamation even if everything you said is true. See, e.g., the case of the Nazi-fetishist MP.)

The Streisand effect is not a thing companies worry about. Because more brand damage = more monetary damages to collect.