How do they find these internships?

Lately I’ve been scrolling through LinkedIn and noticing a pretty solid number of college students landing internships at small PE shops or boutique IB firms. Not talking about the big, structured programs, more like the really small firms that don’t even seem to advertise anything.

Obviously, I get that some of these are nepotism-based. That’s just reality. But honestly, it doesn’t seem like that explains all of them. There are too many people doing this for it to just be connections across the board.

What confuses me is when I actually go look these firms up, a lot of them:

• Don’t have a careers page
• Don’t list internships anywhere
• Sometimes barely even have a functional website

So how are people actually getting these roles?

Are they just:

• Cold emailing partners/MDs directly?
• Reaching out through LinkedIn and networking that way?
• Getting referrals through professors or alumni?

Or is there something else I’m missing here?

Would appreciate if anyone who’s been through this (or knows how it works) could break it down a bit. Feels like there’s some “unwritten process” here that’s not super obvious from the outside.