From Stock Market Wizards interview of Mark Cook:
Another trade I do is the bond ratio trade. The bonds and S&P are like a couple. The bond market always leads, so it is the female, because the male always follows the female. When a couple first start to date, they don't know each other yet, and they will be a bit out of harmony. On analogous markets days, when the bonds go up, the S&P may also go up, but it won't follow very tightly. Then they get engaged, and the relationship becomes closer. Then they get married and go on a honeymoon. When they are on a honeymoon, everything they do is synchronous. On "honeymoon days" in the markets, when I see the bonds go up a few ticks, I know the S&P will immediately follow, and I will buy the S&P for a quick trade. After the honeymoon, when they settle into married life, the bonds will drag the S&P husband along, but they are not quite as joined as they once were. Then the couple gets estranged, or in market terms, whenever the bonds go up, the S&P will likely go down. Then comes the bitter divorce. On "divorce days" the bonds and S&P will move in exactly opposite directions. Every day, I make a determination of what type of day it is. Today, for example, the bonds were going up, and the S&P was selling off. The Street called it a "flight to quality," but to me it was just a "divorce day."
