The $20 billion in erased market cap was not a reaction to a product flaw — it was a repricing of the incumbent business model. Wealth management firms at Schwab, LPL, and Raymond James have long charged advisory premiums on services that Hazel demonstrated could be automated at $125 a month. Investors did not wait to see adoption rates or advisor churn; they marked down the stock the day the feature shipped. That speed reflects how directly the market connected Hazel's capability to the revenue lines of firms that have…