“As of” is a little phrase but I have a lot to say about it. Although it is very common in business writing it can create ambiguity if used incorrectly.
Ambiguity is caused by the fact that “as of” has three different meanings: on, since or from, depending on the context.
Have a look at these sentences:
The contract enters into force as of 1 January 2022. = on
The contract has been effective as of 1 August 2018. = since
The contract is effective as of 1 January 2022. = from
As you see, the meaning of “as of” is determined by the grammar and wording of the sentence in which it is used. So when you use “as of” it is essential that this grammar and wording is correct for the reader to understand what you mean.
The main area of ambiguity is with “as of” meaning “on”. Most native English speakers understand it to mean “on” in the context of “on and after”, as in the first example above, i.e. the contract enters into force on 1 January and remains in force after that date.
But some native English speakers are happy with sentences like this:
The contract was terminated as of 1 January 2017.
To me this is incorrect because a termination cannot happen “on and after” 1 January, but only “on” 1 January. (Some people might dispute this and say that the fact of the contract being terminated continues after 1 January, but to me this is like saying “I drank a cup of tea as of Monday”, and claiming that it’s OK to use “as of” because the fact of the cup of tea being drunk continues after Monday!) But this usage exists nonetheless.
Another area of ambiguity relates to the use of the Present Perfect tense.
Consider this sentence:
The Company purchased 7,000 m3 of wood as of 16 September 2019.
Does this mean the Company purchased (Past Simple) the wood on 16 September 2019, or does it mean the Company has purchased (Present Perfect) the wood since 16 September 2019? The fact that the writer used the Present Simple might lead the reader to think that all the wood was bought on 16 September. But was the writer aware of his choice of tense use?
In my experience, even advanced non-native English speakers make mistakes with the Present Perfect tense. And in the above sentence, this was indeed what had happened – the writer should have written “has purchased”. So if you are not certain that you can use the Present Perfect correctly, do not complicate your writing by using “as of”.
So, after all that, I suggest you follow the advice of professor of linguistics R. L. Trask: “As of – this stiff business expression is best avoided in most writing; use on, since, or from instead, as required.” (Mind the Gaffe: The Penguin Guide to Common Errors in English, Penguin 2002)
Common Mistakes in Business English 
Great entry. Thanks from Navarra, Spain.
I like your article; I only have one comment to make. Contracts are not so simple as a cup of tea. In fact, they are promissory obligations that are (or might be) effective presently and in the future. Therefore, termination of a contract as of (or as from) a specific point of time is perfectly correct when the termination is meant to include the future duties/effects created by the contract (of course this will depend on the type of the contract and the nature of the obligations it has created).
I am trying to say that contracts and contract obligations are legal terms and should be dealt with accordingly when concern promissory issues (apart from being business terms as well).
thank you
Ram
Ram – I take your point. As I said in the article – this is a disputable area.
I believe “as of” can also mean “until”.
As of now, it’s difficult to tell in a cancer’s early stage which patients have which kind of tumor.
https://www.merriam-webster.com/dictionary/as%20of
Ana – I disagree. As I said in the post, “as of” can mean “on and after”. “Until” means something more like “before and on” – e.g. “Stay there until 5pm” means the person has to stay there for the time remaining before 5pm, and then can go at 5pm.
In your example, “as of now” simply means “now”, or “currently”. It does not mean “until now”. Check out my entry on “until now” here: https://blog.harwardcommunications.com/2010/11/18/until-now/
I have just found this blog, the use of “as of” is something that has been confusing me for a while…so thank you!. I had the same doubt that Ana, now I have more clarity about the difference, basically ‘as of’ as synonymous with ‘until’ can’t be used due to the extent of the time we are talking about. What would be the right way to describe that something has been happening for a while until a specific date (without using ‘until’)? Ex: ” Number of cases presented [UNTIL] Nov 2019″
Luis – I think you mean the “way to describe that something HAD been happening for a while until a specific date”. You can use “to” instead of “until” – e.g. Ten cases were presented from 1 January to 1 March.
What if one were to use “as of” in the past perfect context?
E.g., The Company had purchased 7,000 m3 of wood as of 16 September 2011.
Should it be replaced with “by”?
I agree – I would use “by”.
Thanks for your reply. But let’s say if one were to simply refer to the amount of wood that had been purchased at the time of 16 September 2011 (without any implication of increase or decrease in the years that followed), does using “as of” still sound a bit odd?
Should that be the case (and come to think of it), perhaps I should just stick to using “at the time of” (?)
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How is that term as of used in finance? Does it mean start or end
Hi Sarah – Normally “as of” refers to the start of a period – with its “from” or “since” meaning. But, as I say in the post, it can also be used to refer to an end. Without seeing the sentence and knowing the context I can’t tell you what it means in your case.
Yeah am grateful. This is the statement Insert the screenshots of the two gilt closing prices as of 30 August 2022 from Tradeweb.
This means the closing prices on 30 August.