Almost everyone remembers the number and forgets the test. The threshold is not «revenue above EUR 750 million last year». It is EUR 750 million reached in at least two of the four fiscal years immediately preceding the one being tested.
That second half changes the answer in both directions. A group that crossed the line once on an unusual year stays outside. A group that crossed it three and four years ago is inside now, even with revenue since fallen. Enter the consolidated revenue of the ultimate parent for the four preceding years and the check counts them.
Scope only, not liability — being in scope says nothing about how much top-up tax, if any, is due. Excluded entities are not checked here: government bodies, international and non-profit organisations, pension funds and certain investment funds sit outside the rules regardless of size. Fiscal years shorter or longer than 12 months require the threshold to be adjusted proportionally, which this check does not do.