Interactive Brokers Australia Review: Fees, GST and Custody

The short version

• Cheapest US brokerage we have tracked, and it is not close. A$556 over ten years against A$1,165 at Stake and A$1,380 at Pearler.
• Mid-table on the ASX. Six platforms beat it, including Pearler at A$780 against its A$792.
• The only platform in the set quoting brokerage excluding GST. We restate it inclusive so the comparison is like for like.
• Currency conversion is 0.002% with a US$2.00 minimum. The floor is what you actually pay on most orders, and it turns a percentage into a flat fee.
• No HIN. ASX shares sit with a custodian, not in your name.
• The most complex platform in the set to operate. That is a real cost and it appears in no fee table.

What an order costs

Two things before the numbers. Interactive Brokers quotes its ASX brokerage excluding GST, and every other platform in this series quotes it inclusive. The tables below restate IBKR inclusive so the comparison holds.

IBKR also runs two ASX schedules. The Fixed schedule is the greater of A$6.00 or 0.08% of trade value, excluding GST. The Tiered schedule starts at 0.08% with a A$5.00 minimum and scales down to 0.03%. Tiered exists and can be cheaper on large orders. Our tables model Fixed, because it is the schedule most readers will land on and the one IBKR uses in its own published examples: 400 shares at A$50 gives A$16.00 excluding GST and A$17.60 including it.

Order size, all in, GST restated inclusive

The ASX column is flat at A$6.60 until the 0.08% overtakes the A$6.00 minimum, which happens at A$7,500 of trade value. Below that you are paying the minimum plus GST, every time.

The US column looks broken. It is not. It is flat at A$4.63 across a tenfold range of order sizes, because two minimums bind at once. The US brokerage minimum is US$1.00 per order. The conversion minimum is US$2.00 per order. Together that is US$3.00, about A$4.21, and A$4.63 once GST is applied. On a US order of A$500, A$1,000 or A$5,000 you are paying two floors and nothing else.

Ten years, A$1,000 a month

Read the middle row again. Interactive Brokers is the only platform in our set whose half-and-half decade costs less than its ASX-only decade. Adding US shares makes it cheaper, because the US leg is cheaper than the ASX leg on the same money. No other platform we track does that.

Same platform, first in one table and sixth in the other. That is the whole review in two tables.

The GST point

Interactive Brokers is the only platform of the nine we track that publishes its brokerage excluding GST. The other eight quote inclusive. Put an ex-GST 0.08% in a comparison column next to eight GST-inclusive figures and the platform looks 10% cheaper than it is. Nobody has lied, every individual number is correct, and the comparison is still wrong.

We have restated every IBKR figure in this article inclusive of GST for exactly that reason. When you check the commissions page yourself, expect the numbers to look slightly better than ours until you add the 10%. They are the same numbers.

The conversion rate, and the floor that eats it

IBKR's currency conversion is 0.002%, with a US$2.00 minimum per order, and GST applies for Australian residents. The rest of the market charges somewhere between 0.50% and 0.70%, so on the headline rate IBKR is roughly 250 times cheaper. That sounds like the end of the argument. It is not, because of the minimum, and the minimum is what most readers will actually pay.

Work it through on a A$1,000 conversion. At 0.002%, the fee is 2 cents, so the US$2.00 floor applies instead. US$2.00 is about A$2.81 at the RBA rate of 0.7126 for 18 September 2026, which is about 0.28% of A$1,000. That is not 250 times cheaper than anyone. It is roughly half what the market charges: good, but ordinary.

Now try A$20,000. The floor still binds at about A$2.81, which is now about 0.014% of the order, roughly 40 times cheaper than a 0.55% competitor on the same order.

So the rule is this. The headline rate is almost never what you pay, the floor is, and the floor turns a percentage into a flat fee. A flat fee is cheap on a big order and unremarkable on a small one. Convert A$500 a month and IBKR's conversion advantage is modest. Convert A$20,000 twice a year and it is overwhelming.

Their own comparison table

Interactive Brokers publishes a comparison table of its own, dated 8 July 2026, listing the conversion fees of nine competitors and putting itself at 0.03%. That 0.03% is not the published rate. It is the effect of the US$2.00 floor on a particular order size, expressed as a percentage, and on the right order size it is arithmetically correct.

It is useful as a cross-check and it is not a source, because it is a marketing document produced by a party to the comparison. That is not an accusation, it is how every provider's comparison table works, including ones that would flatter our own referral partner. When a rate in a provider's own table does not match the rate on its pricing page, the pricing page is the one to trust.

Two platforms in one

On US shares, IBKR is cheapest by an order of magnitude. Not by a few dollars, by a factor. US$0.005 per share with a US$1.00 minimum and a 1% cap, plus a conversion cost that rounds to nothing on a large order, produces a decade at A$556 against A$1,165 at the next CHESS sponsored option.

On ASX shares, it is mid-table. The A$6.00 minimum plus GST makes it dearer than Pearler on a small order, and the 0.08% above the minimum makes it dearer than Superhero, Stake and moomoo across the board. It beats Selfwealth and CMC Invest and loses to six others. If your portfolio is mostly ASX ETFs bought monthly, this is not the cheap option. If it is mostly US shares, nothing in this set is close. The Pearler vs Interactive Brokers comparison runs both legs side by side.

Who holds your shares

You do not get a HIN. ASX shares bought through Interactive Brokers are held by a custodian, and legal title sits with the custodian rather than with you.

A HIN would have given you something specific: registration of the holding at the ASX in your own name, portability to another sponsoring broker without a sale, and a broker-to-broker transfer rather than a claim on a company if the broker failed. Under a custodian model your holding is an entitlement recorded in the custodian's books, and recovery depends on the custody arrangements and the insolvency process rather than on a register entry in your name.

That is the trade, stated plainly. It is not a scandal and it is not unique to IBKR: it is the same design decision Superhero makes, and it is part of why both can run cheaper than a CHESS sponsored broker on some order sizes.

Which brings up the point most reviews get wrong. The US leg would be custodial at every platform in this set, because CHESS is an ASX system and does not extend to US shares. The custody question at Interactive Brokers is specifically about the ASX leg. If you only ever buy US shares, the absence of a HIN costs you nothing you would have had elsewhere.

Is Interactive Brokers safe?

Interactive Brokers Australia Pty Ltd holds AFSL 453554, ABN 98 166 929 568. An AFSL means the licensee is authorised to provide the financial services it offers and is subject to ASIC's conduct and disclosure obligations. It does not guarantee the platform's solvency, it does not insure your holdings, and it does not make a custodian model equivalent to holding shares in your own name.

The Financial Claims Scheme covers bank deposits up to A$250,000 per account holder per institution. It does not cover shares, at any broker, custodial or CHESS sponsored. If a broker fails, your shares are not a deposit and the scheme does not apply to them. What protects you is the structure of the holding and the client money rules, which is why the custody section above matters more than the licence number.

Where it wins, where it loses, who it suits

Where it wins

• US shares, decisively. A$556 over ten years against A$1,165 at the next option.
• Large currency conversions, where the US$2.00 floor becomes negligible.
• Fractional US shares, which it offers.
• A portfolio that is genuinely global rather than ASX-weighted.

Where it loses

• The ASX. Sixth of nine over a decade, and dearer than Pearler on a small order.
• Small orders generally, where two minimums stack on the US leg and one binds on the ASX leg.
• Custody, if a HIN in your own name matters to you.
• Usability. This is the most complex platform in the set to operate, and that is a real cost that appears in no fee table. The order ticket has more fields than most readers will ever need, the pricing schedules take reading, and the difference between Fixed and Tiered is not obvious until you have modelled your own order sizes. If you want to buy an ETF in three taps, this is not that platform.

It suits investors with a mostly US or global portfolio, converting meaningful amounts rather than pocket money, who are comfortable reading a fee schedule before they trade. It does not suit ASX-only investors, anyone buying in small monthly amounts, or anyone who wants the simplest possible path from cash to ETF.

Not published: account fee, automated investing and minimum investment. We could not confirm any of the three at source, so we are not stating them.