Google is reported to be recruiting bond traders. So what? They’re a big company, they doubtless have a corporate treasury function (although being Google they’ve probably come up with a much more interesting name for it), they probably need to run their own funds purely to manage the enormous heaps of real and theoretical cash sloshing around the place.
The thing is, these traders will have a secret weapon: the results of your web searches. They can look at search trends to understand what others are looking for, and use this as business intelligence to guide their portfolio. If users in Washington DC start searching for information about breakdowns in relations with China, or City of London users are querying rises in VAT, then the Google team have exclusive information to steer their trading strategy.
This is all legal and above board, but it demonstrates the power that companies such as Google can accrue even without using personal data.