The German cartel office also investigates general abuse of dominant market positions, including monopolies (where one could say that the market doesn't exist anymore).

This double-role of the cartel office makes sense, because the whole point of a cartel is for a group of companies to be able to interact with the market like when they would hold a dominant market position.

There's also the step in between, which are official fusions or buyouts of big companies, which's only difference compared to a cartel is that they're officially talking to one another, not inofficially, but which would lead to one single company holding the dominant market position, at which point you would normally not count that to "cartels" at all anymore.

The headline uses a too literal translation of the German word "Kartellbehörde" [1], which can (literally) mean cartel office, but in this case refers to the federal competition regulator (the "Bundeskartellamt" [2], which has this name for historical reasons).

[1] https://www.linguee.de/deutsch-englisch/uebersetzung/Kartell...

[2] https://en.wikipedia.org/wiki/Federal_Cartel_Office