system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What does an investment banker do?

I am not in any way trying to make points about Wall Street, I'm just interested in what investment banking is and how things actually work.
gpt
If you want to sell your house, you may decide to hire a mortgage broker to help you figure out how much your house is worth on the market and then show your house to potential buyers. If you want to buy a house, you may decide to hire a mortgage broker to show you different houses based on what you want and can afford. Instead of houses, an investment banker helps *companies* buy or get a acquired by other companies.

Most investment bankers spend 80-120 hours a week staring at Excel to model out what the financials of the combined company would look like (that's seriously the industry standard hours; most people quit within a year or two). At the highest levels, however, it's basically a sales job. The managing director knows a lot of people in his specific industry, what companies are worth in that industry based on financial metrics he's memorized over the years, and basically helps arrange buyers and sellers. If the deal goes through, the banker gets a small cut of the transaction.