Some help here.
An investment fund (e.g. a pension fund) is the collection of money from thousands of independent investors in one investment vehicle.
Usually is used a simile (сравнение): a mutual fund is a "pool of funds (or money)" with the collective investment power of an institutional investor.
Now I read the translation someone made for me and I see that he uses the word копилка. Does копилка gives you the impression that in this fund might be even $500,000,000? I think No! It sounds too small modest and innocent word to desctibe an "investing bull".