Just curious, how would airgapping be practical if you need Internet connectivity for your "real work"?

For example, let's say you run a quant trading firm and the algorithms you're concerned about being stolen need connectivity to download live trading info, and then after processing that info they need to communicate buy/sell orders to the outside world.

Are there any methods that could be used that would prevent all communication with a secure system (with an airgap level of certainty) besides the strictly defined data you need to do your "real work"?