I read the following paragraph from investopedia: https://www.investopedia.com/terms/c/convexity.asp If a bond's duration increases as yields increase, the bond is said to have negative convexity. In other words, the bond price will decline by a greater rate with a rise in yields than if yields had fallen. Therefore, if a bond has negative convexity, its duration would increase—the price would fall. As interest rates rise, and the opposite is true.
If I understand correctly, for a vanilla bond with coupon, its duration is always a negative value, right? When investopedia says "If a bond's duration increases as yields increase", it is saying the absolute value of duration increases, is that right?