It went down by $4B the day after he published his post. A one day drop isn't about their products or how they treat their customers.
Ubiquiti had a part to play in their compromise, their products have demonstrably gotten worse and it was clear from everything that came out in the wash. Ubiquiti's market value has gone down for a multitude of reasons.
Sure, Krebs has a part to play in being socially engineered to push a criminals MO. But Ubiquti's market cap also went down because:
* Ubiquti are huge, and it's clear they don't have a good engineering culture, or have one at all and that had a part to play in their compromise with or without Krebs being a willing participant in it at all
* For a several billion dollar company, they don't have appropriate risk strategies or security controls in place that are expected of a business of their size
* Their products have gotten significantly worse over the years and as a consequence of the Covid-19 pandemic and supply chain markets, they haven't got product out the door as quickly as prior
The question isn't if they deserved to lose $4B as a consequence of the hack, it's a question of how much of that $4B market loss is because they're not a well ran business as evident by the hack. Vs. how much of that $4B loss was directly because of Krebs? That's a much harder line to define.