How competitive are spring weeks?

For reference, when I did mine it was about 50 successful applicants out of 2500 people who applied. Most banks will have ~similar numbers to that.

Worth bearing in mind that a lot of applicants are applying to the same banks so the applicant pool more or less overlaps.

A ton of applications are usually discarded based on:

a) online test results not meeting the benchmark

b) video interviews not meeting the benchmark

c) undergrad institution not meeting the benchmark (i.e. obvious non-targets)

d) high school grades not meeting the benchmark

e) CVs being wrongly formatted/empty/ridden with errors

All of this before you even get to any sort of human interaction with an interviewer. And that's if you ever will - e.g. Goldman's process is pretty much entirely done based on a CV + CL and if you pass the sifting stage an online video interview.

Layer on the fact that SWs at some firms (definitely not all) are built to be that firms primary diversity sourcing tool. To the point where some SW programs will be majority female and heavily minority even though it's pretty obvious the actual applicant pool itself is nowhere near that composition when you look at other SW classes or even the types of people applying to these programs in general.

Essentially, the chances of landing interviews at the SW stage largely hinges on whether you clear the benchmarks necessary (high school grades, aptitude test performance, university brand, CV+CL presentation/grammatical quality, etc) at which point it doesn't really matter what the competition is you just have to come across as polished, humble and personable in your interviews. Your chances are even higher for some firms if you're a diversity candidate.

Overall though, I wouldn't sweat SWs so much. They can be complete crapshoots in terms of who ultimately gets offers. Definitely prep and put your hat in the ring but I would focus more of your energy on SA applications (apply EARLY) for the year after.