Presidential election If you're looking to lay money on Obama, wait until the RNC is over. There is typically a bump in the national poll after it ends, and by extension you could expect the same in the lines. Now that the Ryan announcement has been made and the market has reacted, the best strategy should be to take Romney for a unit now, Obama for two units after the RNC, and Romney for a unit after the DNC. That should guarantee you an overlay.
If you're trying to get the best value on Romney, I'd wait until after the third debate. There are probably some overlay opportunities based on the debates as well, because of the order of the topics, most notably foreign policy being the final debate.