Cleared financial futures products provide significant margin efficiencies due to liquidity, transparency and standardization inherent to their market structure. Central limit order books offer the transparent pricing and efficient execution necessary to reduce the close-out period for these standardized, liquid products. This market structure, along with the historical success of clearing houses in stress environments, have led global policy-makers to conclude that cleared financial futures should have shorter margin periods of risk, which results in lower margin levels as compared to standardized financial swaps and the bilateral, over-the-counter markets for bespoke financial swaps. These market structure based- margin efficiencies are complemented by the benefits of having a single clearing house counterparty for offsetting exposures, which provides further margin efficiencies at a portfolio level.