Why is it die Managerin?

Managerin ends in -in, and most nouns ending in -in are feminine: in a German dictionary, 88% of them take die.

All nouns ending in -in
Sense 1
die

Meaning

[1] A female person, (mostly employed) manager in a company

[1] eine weibliche Person, (meist angestellte) Führungskraft in einem Unternehmen

Examples

[1] At the moment there is a lot of discussion about the managers' salaries

[1] Zurzeit wird über die Gehälter der Managerinnen heftig diskutiert.

Declension

1 Singular Plural
Nominativ die Managerin die Managerinnen
Genitiv der Managerin der Managerinnen
Dativ der Managerin den Managerinnen
Akkusativ die Managerin die Managerinnen

Pronunciation

Dictionary entries include material from Wiktionary. Wiktionary