 In comparison to the Normal SABR model, the vanna-volga can easily fit both classical convex and atypical concave smiles ( "frowns" ).
<fluency>  In comparison to the Normal SABR model, the vanna-volga can easily fit both classical convex and atypical concave smiles ( "frowns" ).
 In comparison to the Normal SABR model, the Vanna-Volga can easily fit both classical convex and atypical concave smiles ( "frowns" ).