This week, a major influence on U.S. mortgage rates will be the “Brexit vote on Thursday. It is very difficult to predict the effect on the global economy if the UK were to leave the European Union or whether it would lead to similar votes in other countries. Due to the economic uncertainty which would result, a vote for the UK to exit the EU is expected to be positive for U.S. mortgage rates, while a vote to remain would be negative. As each new poll shifts the odds, investors react immediately. This increases daily volatility, as investors factor the expected outcome into asset prices. For example, the latest poll showed greater support to remain, and mortgage rates have moved higher today.