One AstraZeneca share closed at £122.80 on 30 September 2026. One Nvidia share cost $228.38 the same day, or about £172.58. With £100 to invest, neither looks within reach.
Both are. You do not need a traditional stockbroker, a minimum deposit or a whole share, but you do need the right kind of account, and that choice matters more than the share you pick.
About 0.81 of an AstraZeneca share for £100: how fractions work
Shares on an exchange are bought one at a time. A platform that offers fractional shares buys whole shares and splits them between its customers, so each person owns a portion in proportion to what they put in.
At 30 September prices, £100 buys about 0.8143 of an AstraZeneca share and about 0.5794 of an Nvidia share, before any fees. A fraction pays its share of any dividend and rises or falls exactly like the whole share. Voting at shareholder meetings is another matter: the platform usually holds the shares in its own name, and whether it passes votes on to you depends on the provider.
ISA or general account: fractions are now allowed in both
Owning shares directly means holding them in an investment account. In the UK, that means a Stocks and Shares ISA or a general investment account.
For a while, the ISA rules sat awkwardly with fractions. The rules were changed from 6 April 2024 to make clear that fractional shares can be held in a Stocks and Shares ISA. For most first-time investors, an ISA is the natural home for that first £100.
Outside an ISA, a small portfolio rarely triggers tax, but it does mean records to keep. Inside one, there is nothing to declare.
Choosing the app: four checks before you sign up
Trading 212, Freetrade and Revolut are among the apps that offer fractions. Their terms differ, and on £100 small charges weigh heavily.
- Which shares are available as fractions: the list varies from one platform to another, so check the exact names you want.
- Access to US markets, if Nvidia or Apple are on your list.
- Dealing charges: a fixed fee per order eats a big share of a £100 purchase.
- Currency conversion fees on any share priced in dollars, charged on the way in and on the way out.
Check too how your holdings are protected. Investments held by a UK-authorised platform fall under a separate FSCS investment protection, distinct from the scheme for cash deposits.
From an empty account to your first order
- Pick the account: an ISA in most cases, a general account if your ISA allowance is already used.
- Open it in the app with photo ID, your National Insurance number and details of a UK bank account in your name.
- Pay in £100 by bank transfer or debit card.
- Place the order: a market order buys at the current price; a limit order sets the most you will pay. Many apps only accept market orders for fractions.
- Read the fees and exchange rate on the confirmation screen before you tap.
For US shares, the app will usually ask you to sign a W-8BEN form, which cuts the US tax taken from dividends. It takes a minute and is worth doing on day one.
A fraction carries exactly the same risk as a whole share. Nvidia and AstraZeneca can both lose a large part of their value in weeks. Only invest money you will not need for several years, and keep your emergency savings in an easy-access account, where they belong. If you already bank with Revolut, check what its investment account offers before opening another app, and compare digital banking apps on the same four checks.