The phrase "already assumed that" is correct and usable in written English.
It can be used when indicating that a particular assumption has been made prior to the current discussion or context.
Example: "In our previous meetings, we already assumed that the project would be completed by the end of the month."
Alternatives: "previously assumed that" or "have already taken for granted that".
There's a sense, of course, in which one already assumed that this was the case.
Still, financial markets have already assumed that the central bank will follow the Fed later this year.
The officials concluded that raising tuition would not deter applicants, because prospective students already assumed that Bryn Mawr cost the same as comparable colleges.
The carbon budgets have already assumed that we are going to use gas well on through the 2020s and into the 30s.
Fed officials have already assumed that Congress will pass a major spending program to stimulate the economy, and they are counting on it to contribute to economic growth next year.
It has been already assumed that the bankruptcy proceedings operated to suspend the further administration of the insolvent's estate in the state court, but it remained for the state court to transfer the assets, settle the accounts of its receiver and close its connection with the matter.
4 Stop reading fiction – it's all lies anyway, and it doesn't have anything to tell you that you don't know already (assuming, that is, you've read a great deal of fiction in the past; if you haven't you have no business whatsoever being a writer of fiction).
The trustees' bleak projections already assume that the economy will begin to recover late this year.
Southeast Asian policy elites may already assume that the Trump administration doesn't care about their region.
But for practical purposes, lawmakers and lobbyists are already assuming that $100 billion, and maybe $150 billion, is on the table.
