most market makers are essentially prop trading...they take positions for the firm for % of profit...the bigger question is the # of MM's who made switch to RETAIL....my experience has shown they generally don't do as well because they are waiting around for orders to flow past them......
speaking as an X-NASDAQ MM, I have made the jump (due in part to our parent Bank closing our firms doors) to a prop firm. I did very well as a market maker, worked as one for 2 years, and once decimlization and ECNS became a mainstay we got killed. As far as making the transition, it is apples and oranges. I thought the change would be easy, but I was humbled quickly.. My attitude went quickly from I cant wait to make a killing to, how the hell do I stay afloat... Luckily, I followed the advice of my manager who said to start with 100-200 lots, and after 6 months, I am turning (I think) the corner towards profitability.... As my manager and my CEO both said, take what you learned as a MM and forget it. start over... I didnt believe them, now I do.. needless to say, I ditched nasdaq for the most part and focus on listed...
If you are looking to scalp you will lose trading anything - stocks, indices, currency, etc. That is why most mm's fail. They want to continue to scalp when odds are against them. You have to know charting and market psychology nowadays. Forget the myth that listed stocks are more fair than otc. Specialists will hold your fills and work your orders much worse than MMs.
You need to go check your cholesterol. Check your blood pressure while you are at it too. I hope a moderator removes this comment and Boneheads comment.