Breakdown of Das Gemeinschaftsunternehmen zweier Firmen wird sehr erfolgreich sein.
sein
to be
sehr
very
zwei
two
die Firma
the company
Questions & Answers about Das Gemeinschaftsunternehmen zweier Firmen wird sehr erfolgreich sein.
Why does the number zwei have an -er ending here?
Because the phrase 'of two companies' is in the genitive case. Usually, numbers like 2 and 3 do not change their endings. However, when they stand directly in front of a noun without any article (like der or meiner) to show the grammatical case, they take the strong genitive ending -er. This gives us zweier Firmen.
What happens to zweier if I say 'of the two companies' instead?
If you add the definite article der, that article already clearly marks the genitive plural. Because the article is doing the job of showing the case, the number drops its ending and goes back to normal: Das Gemeinschaftsunternehmen der zwei Firmen.
Why is there an s in the middle of Gemeinschaftsunternehmen?
That s is a connecting letter (often called a Fugen-s). It glues the nouns Gemeinschaft (community or joint) and Unternehmen (enterprise or venture) together. As a helpful guideline, nouns ending in -schaft almost always take a connecting s when they form the first part of a compound word.
Can I avoid the genitive and use von here instead?
Yes, you can. In everyday spoken German, it is very common to replace the genitive with von plus the dative case, which would be Das Gemeinschaftsunternehmen von zwei Firmen. However, using the genitive (zweier Firmen) sounds more professional and is exactly what you would expect in a formal business context like this.