This is the 12172nd most frequent Russian word.
инвестициях
"Инвестициях" means "investments" in English.
The word "инвестициях" here is in the prepositional case, indicating the topic of discussion or content, namely "investments."
Я читаю много книг об инвестициях.
I read many books about investments.
Here, "инвестициях" is also in the prepositional case, used after the preposition "в" to express confidence or specialty in the area of investments.
Он хорошо разбирается в инвестициях.
He is knowledgeable about investments.
In this sentence, "инвестициях" follows the preposition "о," again in the prepositional case, introducing the subject of her investments that the story is about.