The midterm election season has entered its final stretch, and Wall Street is busy drawing up game plans for a range of scenarios. Yet, in a fortuitous turn of events, the best outcome for markets is also looking like the likeliest one. Investors have become increasingly confident that Democrats will take the House of Representatives in November, while assigning a slight edge to Republicans in the Senate.

To many market watchers, this is the ideal setup with least risk of disruptive policies.