BizWritingTip reader: “We are having a debate in our office about the use of ‘as of’ or ‘as at’ to describe a statistic that pertains to one point in time. I think ‘As at December 2010, the number of X in Y program was Z’ is correct.”
BizWritingTip response: This is quite an interesting point. Most people are accustomed to using “as of.” However, when providing a snapshot of a particular position on a certain date, “as at” is the correct term. You will find it often in accounting.
“As at” means as it is at that particular time only. It implies there may be changes.
As at 9 a.m. today, 30 people were registered for the event.
“As of” means as it was or will be on and after that date.
As of April 1, there was no more snow to shovel.
We will no longer accept proposals as of May 15.
Note: In North America “as of” is what is commonly said, and a Google search shows “as of” to have more than eight times as many responses as “as at.”
And so dear BizWritingTip reader, you can tell your office that you are correct in this particular instance.