If you manage your own rack, all you are doing is uploading a strategy and letting it run, returning the executed trades to your own inhouse systems for booking

If you manage your own rack, all you are doing is uploading a strategy and letting it run, returning the executed trades to your own inhouse systems for booking. If a third party provider (there are several which offer this service) manages the rack, router, host infra, and provides you with the virtual guest OS, or going one step further with the application into which you load the strategies, then it's much easier to "right size" the infrastructure you actually need. As others have pointed out, the pain point is multicast into the VM. Drop a packet = you lose money. All that said, some trading is going the other way, RFQ based flows with 30 second quote lifetime, which is perfectly suited to the cloud and it could well be the nature of what is traded moves away from volatility based products (options) to value driven (bonds, funds).