Corporate earnings season is starting to kick into high gear. Alcoa is expected to post their earnings after the market closes today. Therefore, it will have an impact on overnight and early morning trading tomorrow. This company isn't necessarily key to gauging economic strength for the bond market, but it is the first Dow component that posts earnings each quarter. Since it is the first look into Dow-related earnings, it draws plenty of attention in the markets. However, there are plenty of other earnings releases that will also be in the spotlight. Generally speaking, weaker corporate earnings translates into stock selling that makes bonds more attractive to investors. As bond buying pushes prices higher, yields fall and mortgage rates tend to track bond yields.