How big a deal would Brexit be for the world economy?

If the UK votes to leave the EU, there would probably be some negative fallout for the UK itself and other European economies due to the resulting uncertainty about their future economic relationship. But this should prove short-lived as all parties would be likely to reassure investors that they intended to reach a new agreement which largely preserves the status quo. Over the long term, Brexit could have major political implications for the EU by encouraging other countries to leave and/or opening the door to closer integration. But any global economic implications should be very limited.