If NYSE has market makers, what is the role of NYSE ARCA which is an ECN
Electronic trading is many orders of magnitude cheaper and more liquid than floor trading and is rapidly displacing it. Stil, electronic trading accounts for 79% of stock trading volume in the U.S. Polcari is losing the battle. Floor trading is still offered, but it's only used for bulk orders, so electronic trading is servicing small trades at minimum prices while floor trading is now the concierge service. I would say it's a bit more complicated than that. Do you understand what a market maker does?  An ECN (electronic communication network) is a virtual exchange that works with market makers. Using a rebate structure that works by paying for orders adding liquidity and charges a fee for removing liquidity. So liquidity is created by encouraging what are essentially limit orders, orders that are outside of the current market price and therefore not immediately executable. These orders stay in the book and are filled when the price of the security moves and triggers them.  So direct answer is NYSE ARCA is where market makers do their jobs. These market makers can be floor traders or algorithmic. When you send an order through your brokerage, your broker has a number of options. Your order can be sent directly to an ECN/exchange like NYSE ARCA, sent to a market making firm like KCG Americas (formerly Knight Capital), or internalized. Internalization is when the broker uses an in house service to execute your trade. Brokerages must disclose what they do with orders. For example etrade's. https://content.etrade.com/etrade/powerpage/pdf/OrderRouting11AC6.pdf This is a good graphic showing what happens in general along with the names of some common liquidity providers. http://www.businessweek.com/articles/2012-12-20/how-your-buy-order-gets-filled
I don't quite understand the NYSE argument that the credit system helps NASDAQ undercut NYSE on pricing and force brokers to trade on NASDAQ. I thought if you were trading a stock listed on NASDAQ, you traded through them and if you were trading a stock listed on NYSE, you'd trade over there. The choice of exchange coming down to the stocks you want to trade more than anything. Are the exchanges also acting as endpoints on trades for securities listed on the other exchange? I think Infochimps has what you are looking for: NYSE and NASDAQ. "Yes there are huge number of parts in the chain. Entire careers can be made out of handling clearing and settlement (back office) work for banks, exchanges, and trading houses. Even more so in the old days when this had to be done by hand, but obviously now everything is electronic. I can provide some insight into your questions, at least on the trading side.  Brokers in many cases have their own brokers or their own trading operations. They will have their own order entry and risk control systems, so that is all proprietary, but it usually doesn't involve more than send buy/sell Y shares of name X to venue Z at price P with extra instructions A,B,C,D,E. Eventually an order will make its way to a direct market participant who sends an electronic order directly to an exchange.  Note that when you say market, you should be referring to such ""exchanges"". In the US these are the NYSE, NASDAQ, and so on. When you are talking about futures there is the CME, CBOT, and so on. In Europe there is the EUREX and so on. The ""market"" refers to all these exchanges together which all have their own order mechanisms and matching engines. In many cases exchanges will route orders to other exchanges depending on the specific country's trading rules. Exchanges compete with each other by fee and liquidity offerings, which are shouldered directly by market participants.  Another detail is that each market participant has its own clearing firm, which has prior credit lines established with the market participant and a central clearing house. Like you said as soon as an order is matched, the exchange where the order takes place hands the trade over to the clearing house where the trade is then settled between the clearing firms representing either side of the trade. Clearing disputes happen at this step." "There is more than one exchange where stock can be traded.   For example, there is the New York Stock Exchange and the London Stock Exchange.  In fact, if you look at all the exchanges, there is essentially continuous trading 24/7 for many financial instruments (eg US government bonds). The closing price quoted in papers is usually the price at the close on the NYSE.  However, options close after that and so there is after-the-close trading in many stocks with active options, so the price at the close of options trading at CBOE is often used. The ""real"" price is always changing.  But for the purpose of discussion, using the closing price in NYSE (for NYSE listed stocks) is pretty standard and unlikely to be questioned.  Likewise, using Bloomberg's price makes sense. Using some after-hours or small market quote could lead to differences with commonly accepted numbers - until tomorrow :)" Conglomerates don't work. We've seem thay countless times in countless periods in countless places in history... A focused company will always outperform an unfocused company in the long run...     Grocery stores trade at tiny multiples. Tech firms at massive multiples. The instant you buy a 3x EBITDA when you're trading at 15x EBITDA, you've increased the market value of the acquired firm by 5x... * In the 70's, 80's and early 90's there were pinstriped brokers who took orders over the phone from people who wanted to buy and sell. They had a huge competitive advantage over the rest of the market due to the lack of transparency in the market's order book. Therefore you got screwed every time you wanted to trade, ie the markets were less efficient because transaction cost was high. Transaction cost is = bid-ask spread + how much you get screwed by the market insiders.  * In the 90's and early 00's there were automated trading systems that allowed people to conduct trades directly with computers, aka Algorithmic Trading. The markets were more efficient, because spreads became tighter as more people were able to enter the market on this platform (e.g. [Lightspeed](http://lightspeed.com)). The ability for market insiders to screw the general market was lessened because the exclusive access to the market's order book was eroded. Of course some Algorithmic Trading operations had a huge competitive advantage because they had great systems and great people. However it wasn't talked about because those who new about it were making a killing and keeping their mouths shut.   * Then in the mid to late 00's there was co-located algorithmic trading on very fast systems, aka HFT, a natural evolution of Algorithmic Trading. Now market insiders (= people with enough resources to field co-located machines and the the engineer/traders to manage them) expanded their  competitive advantage by discovering the market's order book (as they are able to see orders in a fraction of a second and then act on those orders). However to retract this natural efficiency in the markets you would need to create some kind of set of rules to even out the playing field. How can that be done?   ** Option 1) Transaction tax would just make the markets less efficient by increasing the cost of buying and selling. A generally bad thing because it discourages traders (to put money into stocks), which is of course how the capital markets are supported.   ** Option 2) Create rules to ensure everyone sees the same information at the same time and then permit anyone to use whatever technology they want to act on that information, so that the most efficient trading operations win.    ** Option 3) Create some artificial environment where no-one is allowed to have an advantage:  ensure everyone sees the same information at the same time, ensure everyone has the same technology, and ensure that the people who manage the systems have the exact same experience and intelligence etc...      Of course #2 is how it works, and it is the meritocratic basis which underpins Capitalism. I don't see why people have a problem with it. Yea that example is a little skewed when you made the aum differ by 200%. Those two candidates would never apply for the same role.  Networking is essential to get you looked at but at the end of the day it is still all about risk adjusted pnl.  Not to mention that pnl is really all you have to judge a trader I would say the most challenging fact for this assertion is that HFT firms operate with extremely limited capital bases. For a stock with say 10m shares ADV, even a very large and successful HFT strategy might use a position limit of no more than 5000 shares.  That is to say if you sum up and net the buys and sells for a stock across the day the HFT firm will never exceed 10,000 shares (2x position limits assuming it completely flipped) on a stock that trades 10,000,000 shares on a given day. The high volumes are attained through high turnover, the strategy might trade up to 500,000 shares (or 5% of the volume) attaining a 50x turnover.  But that brings me back to the original point. In the market microstructure literature market impact generally has been found to scale linearly or even sub-linearly for net volume executed.   If I alternate between thousands of 1 lot buy and sell orders, it would be very difficult for me to move the market because the market impact of every one of my buy orders roughly cancels the market impact of my almost exactly equal number of sell orders.   There might be a higher-order mechanism at work, but I'm genuinely curious what you think it might be. How could strategies that attain such small net positions have such out-sized impact on market direction?