An "edge" is the system or methodology that allows you to consistently take money out of a market. From what I've seen "edges" are rarely durable and are usually highly personalized or unique to an individual.
On the floor - an edge could be standing next to your brother-in-law who is filling the deck for Goldman Sachs. Usually on the floor an "edge" was buying the bid and selling the offer - you could make a nice living flipping and scratching 1/32'nds in the Bond Pit. It could be stealing signs being flashed in to the pit from the desk clerk. It could be watching the S&P or Yen CME quotes on the board and picking off CBOT Bond bids or offers accordingly if there was a sufficient intermarket correlation. It could be watching the OTR cash trade and trying to pick off futures bids or offers. In the Pit days there was quite a bit of telephone arbitrage in the seventies and eighties. For example, a couple of guys working together would transmit spot gold trades in the cash market and pick off Comex futures orders in the pit. Same I've heard for the cash Cotton markets versus the pit.
Electronically - I've seen literally dozens and dozens of ways. In the late nineties we used to pick off DTB Bund orders based upon a live CBOT Bond Pit squawk box. I've seen custom programs built to game the order queue and order matching algorithm. I've seen lots and lots of spread arbitrage setups over the years.
Point being - there is no singular definition or ultimate example.
On the floor - an edge could be standing next to your brother-in-law who is filling the deck for Goldman Sachs. Usually on the floor an "edge" was buying the bid and selling the offer - you could make a nice living flipping and scratching 1/32'nds in the Bond Pit. It could be stealing signs being flashed in to the pit from the desk clerk. It could be watching the S&P or Yen CME quotes on the board and picking off CBOT Bond bids or offers accordingly if there was a sufficient intermarket correlation. It could be watching the OTR cash trade and trying to pick off futures bids or offers. In the Pit days there was quite a bit of telephone arbitrage in the seventies and eighties. For example, a couple of guys working together would transmit spot gold trades in the cash market and pick off Comex futures orders in the pit. Same I've heard for the cash Cotton markets versus the pit.
Electronically - I've seen literally dozens and dozens of ways. In the late nineties we used to pick off DTB Bund orders based upon a live CBOT Bond Pit squawk box. I've seen custom programs built to game the order queue and order matching algorithm. I've seen lots and lots of spread arbitrage setups over the years.
Point being - there is no singular definition or ultimate example.