How does SSF Buy/sell

[Preston]

Good Morning All Before you guys murder me on this chatforum , let me state that i am a novice with regard to share trading. I have recently read the SSF booklet (as provided by Standard Bank)and what i found interesting is that in the active market , if a seller is selling e.g PHM at 14.70 then Standard Bank will sell a SSF at 14.90. The question is why? or am i completely misinterpreting the concept of SSF Thanks