Traders have at least experimented with shortwave too: https://spectrum.ieee.org/wall-street-tries-shortwave-radio-to-make-highfrequency-trades-across-the-atlan

Traders have at least experimented with shortwave too: https://spectrum.ieee.org/wall-street-tries-shortwave-radio-to-make-highfrequency-trades-across-the-atlantic https://spectrum.ieee.org/wall-street-tries-shortwave-radio-...