In the following video, Motley Fool contributor John Reeves takes a look at S&P's downgrade of Berkshire Hathaway's (NYSE: BRK-A) (NYSE: BRK-B) credit rating, from an AA+, to an AA. John highlights the concerns that S&P has with Berkshire at the moment, and also discusses some other factors that may have contributed to the downgrade. He then tells investors whether this is cause for alarm, or simply more background noise.