Can Somebody please tell me why one trader buy and sell at the same time

[#1]

Hi, good morning, I am a complete novice and would like to know why every day, I assume, one trader sells 200,000 STX40s and buys 200,000 with a share difference of about 7cents. Is this a form off "Stop Loss". If, as they are currently, share prices are going down is this a way to average out your stock prices??

[HateGauteng]

Market maker or Fat finger

[#3]

I'm sorry but what I am trying to find out is why does he do this? Is it because he wants to turn over his money. I see he may do the same thing 3 times a day. What hapenns when the price goes down? Does he stop and wait for prices to rise. Is his prinicipal to take a little often, or am I missing the point? regards

[SimonPB]

it is the market maker .. they are always in the market with volumes either side of fair value ensuring that the stx40 trades at fair value ..

[HateGauteng]

My understanding is that the Market Maker is responsible for ensuring enough liquidity in the stx40 and that the stx40 closely tracks the top40 shares.

[#6]

Where do you see this info that the same person is buying and selling?

[#7]

Thanks, now I understand. I have never heard that term before. So a "Market Maker" is probably a large institution that is trying to maintain the liquidity, of in this case, the STX40. By buying and selling at a fair price(small mark up) in volume they allow a free flow of buying and selling, and by doing this thay are ("Making a Market") actually helping the liquitity of this stock. Thanks Again