TL;DR at the bottom. Sorry in advance for any formatting or grammatical errors. English is not my first language.
This is a pretty long one, so hope you’re up for the challenge :)
This all happened five or so years ago while I was working for a proprietary trading firm. The company is a multinational and it had opened a new office in my city a couple of years before I joined them. For those who don’t know, most prop shops (as I understood it) have a very high turnover rate. Just toss everyone in and keep those who stick. The company I worked for recruited every three months. It had space for about 120 traders but the office was never full. Out of the twenty or so who were hired every quarter, only about five managed to make it beyond the three month internship period, and of those, only one - or sometimes none at all - made it past the additional three months probation period. The company was operating in my city for two years before I joined and there were only about four people who I could have called permanent. Everyone else, about another ten, was either on their internship or on probation.
I and about twenty five others were recruited straight out of university. The internship period paid really well for a first job, about twice as much as any other entry level position in other financial institutions plus bonuses once we went live (regardless of whether one is on internship, probation or permanent), and I was really excited.