Quote from lolatency:
Second, the bonus is compenstation given to workers for the fact that they can't trade their own portfolios individually without severe restrictions. For example, some employees are forced by their employer to hold positions for 30 days at a minimum to avoid issues with insider trading, etc. This alone cuts employee's earnings potential because they cannot aggressively make the sort of side income regular Americans can by managing a portfolio actively.
This is an interesting perspective. It is true that you have to adhere to trading restrictions working for a financial company.
However, the premise is that the individual given the guaranteed bonus to compensate for the opportunity-cost would be able to at least make that amount of return on his/her investments without access to information from the company - basically on-their-own as the "regular Americans" do.
That return is then riskless since it is guaranteed, unlike the regular American who can lose all his/her stake.
So if the employee can indeed consistently get better than that bonus, why be an employee at all? Better to take a spot in "Market Wizards". And if he/she can't consistently do better, then they are getting the bonus for underperforming.
And if Goldman didn't need the $$$, why give up it's leverage as an Investment Bank?