glenn
"But the traders don't move the spreads. With an electronic futs exchange, everything is controlled by computer including the spread. There are no market makers, just traders and a computer system offering prices and taking orders.
The traders simply decide whether to accept the prices offered or not.
It's just that sometimes e.g. the opening gap, the behaviour of the spread is very similar to a real human MM, and just makes me wonder why."
the exchange computer does not "control" the spread, it provides the inside ask and bid price from which the spread is derivied - it is just an electonic exchange where anyone can post a price that they are prepared to trade at - or - pick up a contract at a price that someone else has posted at
when you trade on an exchange's electronic system - you are not trading against the exchange ( the exchange makes their money from a cut of the brokerage fee you pay) - you are trading against other traders - they might be private or big companies - you are still just trading with other trading entities
even if you are trading against someone who is a member of the exchange - that is different to trading using the exchanges electronic platform
so the spread is just a reflection of where traders have placed their limit orders and how other traders are taking those orders up
whilst market makers do provide liquidity to markets - you dont need them for tight spreads if you have enough traders trading and especially if they are trading different strategies such as arbing, where they will go short even in a rising market - the estox is heavily arbed both to options and underlying - so is real liquid
and just because a market has market makers does not mean u will get tight spreads - you might get a tight spread when the market is not moving - but the second the market moves, either futures or underlying - the market makes will pull their size which is why you get fast moves in illiquid markets which appeared to have depth at the bid and the ask - the market makers make their money on the spread - but have to arb with the underlying - hence they have to pull the spread if their arb analysis shows an inbalance in the book
the CBOT uses market makers - but the overall lack of liquidity in the Dow mini causes big changes in the spread and fast moves which then retrace straight away when the dow market makers pull the size even when it appeared moments before that there was depth at the bid and the ask - but the S&P emini and Nas emini have real tight and consistent spreads without needing market makers due to all the various participants and high volume
"But the traders don't move the spreads. With an electronic futs exchange, everything is controlled by computer including the spread. There are no market makers, just traders and a computer system offering prices and taking orders.
The traders simply decide whether to accept the prices offered or not.
It's just that sometimes e.g. the opening gap, the behaviour of the spread is very similar to a real human MM, and just makes me wonder why."
the exchange computer does not "control" the spread, it provides the inside ask and bid price from which the spread is derivied - it is just an electonic exchange where anyone can post a price that they are prepared to trade at - or - pick up a contract at a price that someone else has posted at
when you trade on an exchange's electronic system - you are not trading against the exchange ( the exchange makes their money from a cut of the brokerage fee you pay) - you are trading against other traders - they might be private or big companies - you are still just trading with other trading entities
even if you are trading against someone who is a member of the exchange - that is different to trading using the exchanges electronic platform
so the spread is just a reflection of where traders have placed their limit orders and how other traders are taking those orders up
whilst market makers do provide liquidity to markets - you dont need them for tight spreads if you have enough traders trading and especially if they are trading different strategies such as arbing, where they will go short even in a rising market - the estox is heavily arbed both to options and underlying - so is real liquid
and just because a market has market makers does not mean u will get tight spreads - you might get a tight spread when the market is not moving - but the second the market moves, either futures or underlying - the market makes will pull their size which is why you get fast moves in illiquid markets which appeared to have depth at the bid and the ask - the market makers make their money on the spread - but have to arb with the underlying - hence they have to pull the spread if their arb analysis shows an inbalance in the book
the CBOT uses market makers - but the overall lack of liquidity in the Dow mini causes big changes in the spread and fast moves which then retrace straight away when the dow market makers pull the size even when it appeared moments before that there was depth at the bid and the ask - but the S&P emini and Nas emini have real tight and consistent spreads without needing market makers due to all the various participants and high volume
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