Here’s something I’ve learned from the other side of the desk: the summer analyst who doesn’t get the return offer is almost never the one who couldn’t build the model. The model can be taught. The model gets fixed by an associate at midnight and nobody remembers it by Friday. What ends summers — what I see over and over with the candidates who land in my inbox in August needing a Plan B — is the soft stuff. The phone that’s always face-up. The email that went to the wrong David. The intern who checked out the second the work slowed down.
So let’s talk about the rules nobody puts in your offer letter, because those are the ones being graded.
Understand the frame first. As an investment banking summer intern, you are not “trying out a job for ten weeks.” You are in a ten-week, continuous, fully-observed interview, and the people deciding your fate are not just reading your work — they’re watching whether they can put you in a room with a client, hand you something at 11 p.m. without flinching, and never have to think about you twice. Banking runs on trust and discretion, and senior people use a hundred tiny etiquette signals as a proxy for whether you have judgment. Get the small things right and they extrapolate that you’ll get the big things right. It really is that simple, and that unforgiving.
And the math doesn’t help you: most summer classes are bigger than the number of full-time seats. When two interns are technically a wash — and they usually are — the tiebreaker is never the model. It’s who was easy, reliable, discreet, and pleasant to staff. Keep that in your head as you read the rest.
1. Your phone is a billboard. Treat it like one.
Nobody is going to tell you to put your phone away. They’re just going to notice, and quietly file it.
Set it to silent — not vibrate, a buzzing phone on a quiet desk is its own announcement — and check it on breaks, between tasks, or after you’ve left. Face-down in a drawer beats face-up on the desk. And during training or anytime a person is spending their own time teaching you, the phone disappears entirely; glancing at it mid-sentence tells the person investing in you that they’re losing to a notification, and people remember exactly how that feels.
The only rule you need: if you wouldn’t pull it out in front of the most senior person on the team, don’t pull it out at all. Assume they can see you. Eventually they will.
2. The floor is open. Your “private” moment isn’t.
Open floor plans mean there is no such thing as a quiet personal call at your desk. A two-minute chat about dinner plans broadcasts to a dozen people that your head is somewhere other than the deal. If you have to take it, step into an empty conference room or go outside, and keep it short.
Music is a read-the-room situation, not a default. On some desks one earbud signals focus; on others it signals you’re unreachable. Ask early — “Mind if I put in an earbud when I’m heads-down?” — instead of guessing wrong. And if you do, leave one ear open. Nothing irritates a staffer faster than having to tap you on the shoulder because you didn’t hear your name the first three times.
3. The internet restrictions are not a dare.
Firms block social networking sites and personal email for compliance and security reasons that are very real and very regulated. These are guardrails, not a challenge to your ingenuity.
Pulling out your personal phone to route around them is one of those moves that looks far worse than the thing you were trying to do — it reads as evading monitoring, which is a different and much more serious category than a quick scroll ever was. Keep personal browsing to breaks and lunch, do it on your own device away from your desk, and assume every keystroke on a firm machine is logged. It is. And the moment you’re unsure whether something is allowed — moving a file, downloading a tool, anything near personal trading — ask compliance. Asking has never once gotten anyone in trouble.
4. Meetings are auditions. Show up like it.
Every meeting is a small, live impression-forming event, and senior people form those impressions fast.
The phone does not come out in a meeting with senior managers — not even a glance, because a glance is all it takes to read as “checked out.” Walk in prepared: skim the materials beforehand, bring a notebook, write things down by hand. Capturing the action items and then actually following up on them without being asked is one of the cheapest ways an intern can look exceptional, and almost nobody does it.
You don’t need to talk the most. One sharp, well-formed question lands better than five half-baked comments — and when in doubt, ask about scope or next steps rather than offering a take on something above your pay grade. On video, get your name displayed correctly, mute when you’re not talking, put the camera at eye level, look into the lens, and dress exactly as you would in the office. Everyone notices the intern in the hoodie.
5. Email is permanent. Write like it’ll be read aloud.
This is the one I’d tattoo on every incoming class if I could.
Check the recipient before you send — autocomplete firing a draft off to the wrong person is a classic, and it’s avoidable. Proofread. Read your own tone the way the senior person on the other end will read it. Keep it short and skimmable, because they’re reading on a phone between meetings; lead with the point and make the ask explicit. No emojis, no gifs, no slang, including on the internal chat, until you have a real read on the culture.
And here’s the part interns underweight: email is part of the permanent record. It’s retained, archived, and in a regulated shop, reviewable long after you hit delete. Write every message as though it could one day be read aloud by someone you’d rather not have reading it — that single habit keeps you out of nearly all written-communication trouble.
One more, on responsiveness, because it’s etiquette too: acknowledge a request fast even when you can’t finish it fast. “Got it — I’ll have this back to you within the hour” is enormously reassuring to a staffer. Silence reads as either confusion or absence, and neither one helps you.
6. The walls have ears. So do the elevators, the cabs, and the bar.
This is a small industry, and it stays small. In group travel, elevators, taxis, and common areas, assume the person who decides your future is within earshot. Keep it professional, and never — ever — discuss live deals, clients, or names in public space. Confidentiality slips are one of the very short list of intern mistakes that can end a summer the day they happen.
Skip the controversial topics and the off-color jokes; what feels like harmless banter with the other interns gets overheard and remembered by a passing MD, and the downside is real while the upside is zero. And do not underestimate the small communal courtesies — don’t microwave the fish, clean up the conference room, refill the coffee you finished, don’t be the one who leaves the printer jammed. Those micro-behaviors compound into “considerate and easy” or into “low-key a problem.” Same goes double for the intern happy hours: drinks are still work. Pace yourself. The evaluation does not pause because there’s an open bar.
7. Take care of yourself — because depletion shows.
The hours are the hours, and I’m not going to pretend otherwise. But you cannot perform or behave well running on empty, and falling asleep at your desk is a reputation-denter that’s genuinely hard to walk back. Protect your sleep where you can, take the short real breaks, step outside, and stop treating exhaustion as a flex.
Dress for your actual desk — watch the analysts a year ahead of you and calibrate slightly conservative. Show up a few minutes early, especially for anything scheduled, and look like someone taking the internship seriously, because looking the part is half of being treated like it. Then take initiative without overstepping: ask for more when you’re free instead of waiting to be found, help the intern next to you who’s drowning, and stay steady and pleasant at 2 a.m. The one who stays gracious under pressure is the one people fight to staff again.
Now the ones that aren’t on anyone’s etiquette list — and decide more offers than all of the above
Learn how to ask a question. There’s a wrong way (interrupting a slammed associate every five minutes with things you could’ve figured out) and a right way (attempt it, batch your real questions, and bring context): “I tried X, got Y, I think the issue is Z — wanted to confirm before I keep going.” That shows resourcefulness and respect for their time in one move. Knowing when to ask versus when to grind it out yourself is a skill people clock immediately.
Take feedback like a pro. You will get edits. A lot of them, often blunt, sometimes at 1 a.m. Don’t get defensive, don’t over-apologize, and above all don’t make the same mistake twice. Keep a running comments log so you never need the same correction again. An intern who internalizes a note after one round beats a technically gifted one who needs it five times — every time.
Be decent to the people who don’t grade you. The assistants, the staffer, the support teams, the security desk, the other interns. Word travels, and an offhand comment from an assistant to an MD quietly helps or hurts you more than you’d think. It’s also just the right way to behave, which matters separately from whether it’s useful.
Mind the downtime. Slow stretches are the trap. Visibly disengaging the second the work dries up is a tell. Use the lulls — learn the templates, read old deal materials, study the sector, ask who needs a hand. Staying engaged when you could coast is exactly the signal that earns trust.
The bottom line
You’re not just spending a summer — you’re laying the foundation for a career, and the foundation is poured out of conduct as much as competence. Master this stuff and you’re signaling the four things senior bankers are actually scanning for: professionalism, respect, discretion, and the kind of reliability that lets them stop worrying about you.
I’ll say it plainly, because it’s what I tell every candidate who lands in my office after a summer that didn’t convert: your judgment and your character carry as much weight as your technicals, and usually more — because the technical gaps can be trained and these can’t. The interns who turn the summer into a full-time seat are rarely the most naturally gifted in the room. They’re the dependable ones, the self-aware ones, the ones nobody has to think twice about. Be that one, treat every interaction as the interview it actually is, and the offer tends to take care of itself.