I am not a banker and so some of my terms might be wrong, also some of my views are probably wrong, but here's my lay understanding of the work for front office IB folks in groups that do deal advisory(so not sales & trading or 'desks' or backoffice things) -- any industry group like "Natural Resources" or "Tech"(which are financially generalist i.e. they do all sorts of deals for X type of company) or specialist deal thing like M&A or LevFin(which are industry generalist -- they do one type of deal for all kinds of companies).

A large majority of the work that these people are staffed on is either time sensitive proposal work, preparing to pitch Acme Widgets on why Our Bank should Lead Their Deal(which bankers call 'bake offs'), or actual live deals(if your bank won the work). So if you are a junior, a lot of it is event driven, you respond to emails, edit requests(of decks, the model, etc), you are available for the client(which is usually CEO, CFO, etc) basically all the time. These things run a lot leaner than I expected, like, the group involved in orchestrating the prepping of a a filing(basically project managing dependencies with legal etc) is not tons of people, and only a few of them "own" the various big moving pieces. The work is not complex in the sense that cutting edge engineering might be(it isn't quant stuff), it is fairly simple mathematically(in the same way as accounting), but the skills of a banker are more attention to detail, dealing with clients, enduring a lot of suffering, formatting decks, etc.

Additionally -- these systems aren't that sophisticated(in a Software Maturity sense, they are obviously sophisticated financial tools), models are xslx workbooks that are sent around or uploaded to shared file systems, etc. (Aside: if someone could build github for bankers...) I am told the work is hard to split because one person is DRI for model, etc, and they just own it through the process. It is pretty shocking/cool(or scary?) how few people and how junior they are underlying "Big Deals" e.g. major IPOs. A lot of times you'll have like, an associate(1-3 years out of an MBA, usually no banking before) + an analyst(1-2 years out of undergrad) largely running a deal with the supervision of someone higher up, a VP or ED, and then a Managing Director(the banking equiv of "partner" though most of the banks aren't actually partnerships anymore) who is the 'face' and won the deal and communicates at a high level with the clients. Obviously they fan out to specialized back office depts that do stuff like underwriting, risk, legalese(securities are after all contracts), etc.

I've heard from some people in PE at big funds that are known to run super lean(like, 3 people running a big deal) that they do it on purpose as a philosophical choice to make more money(bigger pie, fewer slices), but the big banks are not afaik like that.

I think traditionally junior bankers spent a ton of time waiting in the office for someone to drop something on them late at night, which covid has improved because everyone can live their life at home if they are waiting -- but the market is so hot that people are just staffed on more deals and deals are staffed with fewer people.

These people do get a lot of experience really fast, and they do get a pedigree that lets them get hired at better opportunities(either money wise or balance wise or both), but it sucks hard and the banks don't really try to hide it e.g. the "Protected Weekend" where you are supposed to _really_ get a weekend off once a month is a pretty new thing.

The other thing that sort of shocks me to hear is that even if you stick it out and make MD, it still sucks. You make a lot more money, but you are still on calls at 11pm on weekends all the time.

Matt Levine has a more eloquent response to this in today's money stuff.

"The point of being an investment-banking analyst is to develop, through endless miserable repetition, a muscle memory for certain core skills. One of those skills — surely the least useful, but also the most salient — is formatting presentations. The other ones are, like, building financial models, talking confidently in meetings after limited hasty prep, etc., basic building-block skills of financial analysis that will serve former investment bankers well in a variety of future jobs. (Mostly private equity but still.) The presentation-formatting thing is totally dumb, but it is an easily legible signal, a brown M&M test of investment banking preparation. If you just automatically and instinctively build a properly formatted PowerPoint deck for everything,[2] people will trust you to build a leveraged buyout model or run due diligence on an acquisition. I’m sorry these analysts are sad and planning to leave Goldman, but at least they will leave with marketable skills."