A unit trust vs a tax free savings account is not really a choice between two products. A tax free savings account (TFSA) is a tax wrapper, and a unit trust is one of the investments you can hold inside it. The practical question is how much of your money belongs inside the wrapper, where returns escape tax, and how much has to sit outside it in an ordinary taxable unit trust.
Wrapper and Product Are Different Things
A unit trust is a pooled fund managed by a professional manager who invests in shares, bonds, money market instruments, or a mix, and you own units that represent your share of the pool. You can buy that fund in a normal taxable account, or you can buy it inside a TFSA.
A TFSA is not an investment in itself. You open the account with an authorised provider and then choose what to put in it. Qualifying investments include unit trusts, exchange-traded funds classified as collective investment schemes, fixed deposits, certain endowment policies, and linked investment products.1South African Revenue Service. Tax Free Investments The same unit trust can therefore exist in two places at once in your portfolio: one copy inside the TFSA, one copy outside. The fund performs identically. Only the tax bill differs.
The Tax Difference Is the Whole Point
A unit trust held in a taxable account exposes you to three separate taxes every year. Inside a TFSA, all three fall away.1South African Revenue Service. Tax Free Investments
Capital Gains Tax
Sell units in a taxable unit trust at a profit and you trigger capital gains tax. Individuals get an annual exclusion of R50,000, and 40% of any gain above that is included in taxable income, producing a maximum effective CGT rate of 18%.2National Treasury. Budget 2026 Tax Guide Switching from one fund to another counts as a disposal and is treated the same way. Inside a TFSA, no CGT applies to any sale, switch, or withdrawal, no matter how large the profit.
Dividends Tax
South African companies apply a 20% withholding tax on dividends before the cash reaches you.3South African Revenue Service. Dividends Tax A R1,000 dividend becomes R800 in a taxable account. In a TFSA you receive the full R1,000, and reinvested over decades that gap compounds.
Interest Income
Interest from bonds or money market instruments in a taxable unit trust is added to your income and taxed at your marginal rate. The annual interest exemption is R23,800 for individuals under 65 and R34,500 for those 65 and older; anything above is fully taxable.2National Treasury. Budget 2026 Tax Guide Inside a TFSA, all interest is exempt with no cap.
Each tax trims a slice from your annual return. A taxable fund earning 10% might deliver 7% or 8% after tax, depending on your bracket and the mix of gains, dividends, and interest. Over 20 or 30 years, that drag costs real money. One point to note: the TFSA wrapper does nothing about fund fees. A 1.5% total expense ratio costs the same inside or outside, so compare the total investment charge when picking what to hold.
The Contribution Ceiling Forces the Choice
Section 12T of the Income Tax Act caps TFSA contributions tightly. From 1 March 2026, the annual limit is R46,000 and the lifetime limit stays at R500,000 per person.1South African Revenue Service. Tax Free Investments Both limits aggregate across every TFSA you hold.
Go over either number and SARS charges a 40% penalty on the excess, collected as normal tax.1South African Revenue Service. Tax Free Investments That penalty erases any tax saving you were trying to get in the first place. Unused annual allowance does not roll over. Contribute R30,000 this year and the remaining R16,000 is simply gone.
Taxable unit trusts have no limits of any kind. You can invest any amount, any time. For anyone with more than R500,000 to put to work, the TFSA shelters only part of the portfolio and ordinary unit trusts carry the rest.
Withdrawals and the Re-Contribution Trap
Both accounts let you take money out at any time. Neither locks you in. The structural difference is what happens when you want to put money back.
In a taxable unit trust, withdrawals and re-investments are routine. The only tax event is any CGT on the sale itself.
In a TFSA, every rand you put back after a withdrawal counts as a fresh contribution against your annual and lifetime limits. Contribute R200,000 over the years, withdraw R50,000 for a short-term need, then reinvest that R50,000, and SARS reads your lifetime contributions as R250,000.1South African Revenue Service. Tax Free Investments Investment growth that stays in the account does not count against the cap, but any capital you remove and replace does. With only R500,000 of lifetime space, dipping in permanently shrinks the sheltered portion of your portfolio.
That makes the TFSA a poor home for an emergency fund, a house deposit you plan to use within a few years, or money you are actively trading. Keep that money in a taxable unit trust where moving it around has no structural cost.
Switching Funds and Changing Providers
Rebalancing is cheaper inside the wrapper. In a taxable account, switching from one fund to another is a disposal, and the CGT bill sometimes keeps investors stuck in underperforming funds. Inside a TFSA, switches between qualifying funds trigger no CGT.
You can also move your TFSA from one provider to another. The transfer must complete within 10 business days, and a provider is not required to process more than two transfers per tax year for the same investor. A provider-to-provider transfer is not treated as a new contribution and does not use any of your limits, provided the transferring house issues a contribution-history certificate so the receiving house can track your position.4National Treasury. Regulations in Terms of Section 12T(8) of the Income Tax Act 1962 on the Requirements for Tax Free Investment
Which Should You Fund First
If you are investing for the long term and still have TFSA room, fill the TFSA first. The tax saving is automatic and guaranteed, and there is no scenario in which paying tax on your returns beats not paying it, as long as you leave the money alone.
A taxable unit trust is the right vehicle in two situations. First, once you have used your R46,000 for the year or hit the R500,000 lifetime cap, anything further has to sit outside. Second, for money you may need to touch within a few years, the taxable account is actually better, because withdrawing and re-investing carries no structural penalty.
For high earners the answer is both accounts, in that order: R46,000 into the TFSA each year, everything beyond that into taxable unit trusts or other investments. The lifetime cap means the TFSA will only ever be one piece of a larger portfolio, but it is the piece that compounds most efficiently.