<Para ID="Par1">We consider the problem of giving a robust, model-independent, lower bound on the price of a forward starting straddle with payoff <InlineEquation ID="IEq1"> <EquationSource Format="TEX">$|F_{T_{1}} - F_{T_{0}}|$</EquationSource> </InlineEquation>, where 0T <Subscript>0</Subscript>T <Subscript>1</Subscript>. Rather than assuming a model for the underlying forward price (F <Subscript> t </Subscript>)<Subscript> t≥0</Subscript>, we assume that call prices for maturities T...</subscript></subscript></subscript></subscript></subscript></equationsource></inlineequation></para>