It seems incredibly obvious that making lots of long-term investment when the future of the UK is so completely unknown would be a risky move. So you cut investment for a bit, and we see what happens later.
More specifically there are concerns about storing EU-citizen data outside the physical EU and in ways which could not comply with the requirements of EU privacy laws.
This is in addition to the legislative issues about handling EU data, which may or may not be side-stepped by UK keeping all laws on the matter. But considering we'll badly need a free-trade agreement with the US right after we leave, that's likely one of the areas where the Americans will ask us to drop shields...
Not disagreeing, just finding this information interesting
https://news.ycombinator.com/newsguidelines.html
"Please don't insinuate that someone hasn't read an article. "Did you even read the article? It mentions that" can be shortened to "The article mentions that."
Of course UK might leave before such ruling.