Phil's points about using established phrases for the industry ("year over year", etc) are worthwhile, as they can make it much easier for your audience to understand your meaning, but regarding the explicit question, the sentence as provided is grammatically correct, yes.
Regarding the placement of the "supported" phrase, it would be perfectly acceptable to place it either at the beginning or the end of the sentence (both are grammatically correct). Where you put it really depends on which part of the sentence you want to emphasize most.
Pretax profits surged 280% year over year to US$60 million, supported by a doubled profit margin and a 90% increase in revenue.
This emphasizes the pretax profits as being the most important part of the sentence, whereas the profit margin and revenue increases are a less important (explanatory) point.
Supported by a doubled profit margin and a 90% increase in revenue, pretax profits surged 280% year over year to US$60 million.
This sentence puts the emphasis on the profit margin and revenue as being the most important point being made, whereas the profits are a secondary consideration.