[cynicalkane]

At my company, bonuses are based on a standardized bonus earnings target. The target is unpublished, but the company keeps people updated on the approximate chance of the bonus meeting certain percentage benchmarks. Keeps people from being unpleasantly (or pleasantly) surprised by too great a degree.

When bonuses are paid out this way, I see them more as a way to sort of vary compensation based on market health, while still guaranteeing a fixed salary. They're performance incentives inasmuch as employees are compensated based partly on performance and partly on how well the industry is doing, making compensation market-driven in a loose sort of way.