I suspect that's partly due to its proximity to Winnipeg; a great deal of the cross-border traffic with Canada flows through MN. But MN has a disproportionate number of big industrial companies: http://en.wikipedia.org/wiki/Economy_of_Minnesota
Looking at the states, I think corporate headquarters might be a big part of it. Why else would Arkansas be on the list of net givers? (And Minnesota has a relatively many corporate headquarters.)
If you're going to downvote a neutral comment like this, it would help to explain why.