And one can certainly question how socially useful it is to build optic fiber or microwave  8  See Maureen O’Hara (2014), “High Frequency Market Microstructure (PDF),” working paper, April, p. 2. BIS central bankers’ speeches  3  networks just to trade at microseconds or nanoseconds rather than milliseconds.
The cost of these technologies, among other factors, may also be driving greater concentration in markets, which could threaten their resilience. The type of internalization now done by dealers is only really profitable if done on a large scale, and that too has led to greater market concentration. A number of observers have suggested reforms for consideration.