### Comment:
From your  link: 
  
 'Thereupon, the return on a box spread is “locked-in” 
 at a fixed amount equal to the difference in the 
 strike prices less the initial net payment of premium. ' 
  
 I read that as 'can't go tits-up'

### REPLY:
Yes, It basically a loan garanteed through the options clrearing houses and a rho play. If you buy the box you’ll get paid whatever interest is at expiration, it’s like owning t-bill but more flexible, if you use European style options.

### END.