Start Rate:

The start rate is the rate during the initial period of the loan, which could be one month or a year or more. Most ARM's have teaser rates at the beginning, rates that are artificially low (below market prices) to ease the transition into a mortgage and to make their loan more attractive. After their initial period, the interest rate goes toward its fully indexed value, i.e. index + margin, but the rate adjustment is usually limited by periodic caps. Periodic caps and lifetime caps Caps are preset limits on how much your rate or payment may adjust in any given period.