Goldman Sachs is in the midst of raising another private equity fund, this one will be in the $20 million range. The Blackstone Group is also aiming high; it plans to soon raise an $18 billion deal. So this makes for an interesting relationship between the two. Goldman Sachs is a huge player of course; it is investing alongside KKR and Texas Pacific in the TXU deal, and there has been speculation that Blackstone may enter the fray. Goldman Sachs is also a broker dealer with whom Blackstone does a lot of business. So the Blackstone Group may be a client and a competitor. It was this sort of thinking that led to the discredited notion that brokers can't run PE operations. But Goldman Sachs, which will not be an underwriter of the Blackstone IPO, and others are making it work. It's too late to go back now.  

For more:
- here's an AP article