Opening Your First Investment Account — Including Custodial Accounts Under 18

ℹ️ This is education, not investment advice, and not a recommendation of any broker. It walks the mechanics of opening an account. What (if anything) you put in it is your decision. ⚠️ Version note: broker sign-up flows and account types change. Last checked: 25 July 2026.

What you'll have at the end

• The right account type chosen for your situation — including the custodial route if you're under 18
• A brokerage account opened (or set up with a parent/guardian) and verified
• Clarity on the costs and settings that quietly matter

Prerequisite

• MN-01 — What Are You Actually Buying and MN-03 — Index Funds and ETFs. Open the account after you understand what a broker and an index fund are — not before.

The account is a container, not a decision

Opening a brokerage account doesn't invest anything or commit you to anything. It's just a container that lets you hold and trade investments — like opening a bank account before you've decided what to save. Getting the container right (the type, the costs, the safety checks) is this lesson. Filling it is a separate, later choice.

This is the fork that trips up under-18s. In most countries you cannot open a brokerage account in your own name until you're 18. The routes:

✅ Check: you know which type applies to you, and (if under 18) which adult would open the custodial account with you.

If it moved: names differ by country (custodial, minor account, junior account). Search your broker for "under 18" or "minor" — if there's no such option, that broker doesn't serve minors; pick one that does.

Ignore flashy apps. Compare on four things:

1. Serves your situation — supports custodial accounts if you're under 18, and your country.
2. Costs — commissions per trade, account fees, and the spread/FX costs (MN-01, MN-12). "Zero commission" often hides cost elsewhere.
3. What you can hold — can it buy broad index funds/ETFs (MN-03)? That's the point for most beginners.
4. Safety — is it regulated in your country, and are client assets protected up to some limit? This is non-negotiable.

✅ Check: you've picked a broker that is regulated, serves your situation, lets you buy index funds, and whose costs you can name.

If it moved: regulator and protection-scheme names differ by country. Find your national financial regulator and confirm the broker is on its register before going further.

Start the sign-up. Expect to provide:

• Identity — legal name, date of birth, a government ID (for a custodial account, the adult's ID and yours).
• Tax details — a national tax/insurance number in most countries.
• Bank link — to move money in and out later.

[Screenshot: the broker's account-opening form (personal details step), values blurred.]

✅ Check: you've completed the application and the broker confirms it's received (often "under review").

If it moved: ⚠️ Never enter your ID, tax number or bank details on a site you reached from an ad or a message. Type the broker's address yourself and confirm the regulator listing (Step 2). This is exactly where phishing (TC-11) targets people.

Most brokers require identity verification (a photo of your ID, sometimes a selfie) before the account activates. Then linking a bank account lets you transfer money.

• You do not have to deposit anything to have opened the account. Opening and funding are separate steps.
• If you do fund it, start with an amount you could lose without it mattering — the account being open is the lesson's output, not a rush to buy.

✅ Check: the account is active (verification passed). Whether you've funded it is up to you.

Before you ever trade, look at three things:

• Order types — know the difference between a market order (fills now at the going price) and a limit order (fills only at your price). MN-01's order book explains why this matters.
• Fees — find the fee schedule and read it once. Know what a trade and an FX conversion cost.
• Two-factor authentication — turn it on (TC-11). This account can hold money; secure it like it.

✅ Check: 2FA is on, and you can state what one trade would cost you in fees.

Common mistakes

• Under-18s trying to open an adult account. Use the custodial route with a parent; don't fake a birth date — that's fraud and gets the account frozen.
• Reaching the broker from an ad or DM. Always type the address yourself; verify the regulator. Investment phishing is rampant.
• Chasing "zero commission" without checking spreads/FX. The cost moved, it didn't vanish (MN-12).
• Skipping 2FA. A money account without 2FA is a soft target.
• Rushing to buy the day it opens. The account being open is the goal here. What goes in it is a separate, considered decision.

Exercise (30 min)

1. Identify your account type (custodial or individual) and, if under 18, the adult who'd open it (Step 1).
2. Compare two brokers on the four criteria (regulated, serves you, holds index funds, costs) and pick one (Step 2).
3. Open the account (or, if under 18, set it up with your parent/guardian) and complete identity verification (Steps 3–4).
4. Turn on 2FA and write down what a single trade and an FX conversion would cost (Step 5).
5. Do not feel any pressure to deposit — note that opening and funding are separate.

✅ Finish check: you have an active investment account (or a custodial one set up with an adult), 2FA enabled, and its trade/FX costs written down.

Cheatsheet

THE ACCOUNT IS A CONTAINER — opening ≠ investing

1. TYPE     → under 18: CUSTODIAL (a parent opens it for you) · 18+: individual
2. BROKER   → regulated in your country · serves your situation · can buy index funds · known costs
3. OPEN     → ID + tax number + bank link.  TYPE THE ADDRESS YOURSELF (never from an ad/DM)
4. VERIFY   → identity check activates it. Opening and FUNDING are separate — no rush to deposit.
5. SETTINGS → market vs limit orders · read the fee schedule · turn ON 2FA

Regulated + protected client assets = non-negotiable. Under 18 → custodial, never a fake birth date.

Next lesson: MN-10 — The Anatomy of a Scam (L2) Related: MN-03 Index Funds and ETFs (L1) · MN-12 The Real Cost of Money (L2) · TC-11 Security Basics (L1) Path: Reading the Market — 5/6