Yes it is. SBD is pegged to dollar in such a way that how much of 1 STEEM you get for 1$ Is equal to one SBD. Now suppose one STEEM is worth 4 dollars. Then one SBD will be equivalent of one dollar worth steem meaning 0.25 steem. Like if one steem was worth 10 cent you would get 10 steem for 1 sbd so that sbd always maintains a ratio with steem and always be equivalent to 1 dollar. But sbd price flactuates and it was once more than 12 dollars.