Form 1099-B: 2026 Guide for Australians with US Investments

Form 1099-B is an IRS document issued by US brokers and trading platforms. It reports proceeds from the sale of stocks, ETFs, options, and certain crypto assets. If you hold investments with US-based platforms—think Charles Schwab, Robinhood, or even some crypto exchanges—you may receive a 1099-B each January or February, summarising your taxable US investment activity.

• Capital Gains Reporting: The form details your gross proceeds, acquisition costs, and net gain or loss—crucial for calculating capital gains tax (CGT) in both the US and Australia.

• Tax Residency Implications: Even if you’re a full Australian tax resident, the US may withhold tax on certain gains, and you’re still required to report those transactions to the ATO.

• Crypto and ETFs: As of 2026, more US exchanges are required to issue 1099-Bs for crypto trades, making digital asset reporting harder to avoid.

Failing to reconcile your 1099-B with your Australian tax return can trigger ATO red flags, especially as data sharing between the IRS and ATO continues to strengthen under FATCA and CRS agreements.

This year, several key changes are in play:

• Expanded Broker Reporting for Crypto: US crypto exchanges now issue 1099-Bs for a broader range of digital asset transactions, following expanded IRS guidance effective from January 2026.

• Australian Tax Office Data Matching: The ATO announced in early 2026 that it will intensify its data-matching program with the IRS, specifically targeting unreported foreign investment income and capital gains.

• ETF and Mutual Fund Transparency: US brokers must now break out more detailed cost basis and holding period data on 1099-B forms for ETFs and mutual funds, which can simplify (or complicate) your Australian CGT calculations.

• Withholding Tax Clarifications: Updated IRS rules clarify how withholding on US-source gains (such as from certain ETFs) should be reported—information you’ll need for claiming foreign tax offsets in Australia.

For Australians, these updates mean more comprehensive reporting and less room for error—or omission. If you’re using an Australian accountant, be sure they’re familiar with the nuances of US tax documentation and the latest ATO guidance.

Here’s how to stay compliant and avoid double taxation headaches:

• Cross-Check Everything: Don’t just plug the 1099-B numbers into your ATO return. US and Australian tax years differ (calendar vs financial year), and foreign exchange rates apply. Use the ATO’s official rates for conversion.

• Declare All Gains, Even If Withheld: If the IRS has already withheld tax on your gains, you still need to declare the income in Australia. Then claim a foreign income tax offset to avoid double taxation.

• Keep Detailed Records: The 1099-B may not capture your true cost base, especially if you transferred assets between brokers or acquired them before moving to Australia. Keep your own records and reconcile them with the form.

• Watch for Crypto Complexity: If you receive a 1099-B for crypto, cross-check it with your own transaction logs. Many platforms don’t capture the full acquisition history, which can impact your CGT calculation.

• Seek Expert Help for Complex Cases: If you’ve been trading actively, have multiple brokers, or have held US investments long-term, the cost base and tax implications can get tricky. Professional advice can save you money—and stress.

Finally, be proactive. The ATO’s cross-border data-matching program is more sophisticated than ever in 2026. Failing to properly report your US investment income or gains can result in audit activity, penalties, and interest.

Consider Sarah, an Australian resident who holds Tesla and Apple shares via a US brokerage. In 2024, she sold some shares and received a Form 1099-B in early 2026, showing:

• Gross proceeds from Tesla: $10,000 USD

• Cost basis: $7,500 USD

• Net gain: $2,500 USD

• US withholding tax: $375 USD (15%)

Sarah must:

• Convert the sale and cost figures to AUD using ATO’s 2024–25 exchange rates

• Report the capital gain in her 2024–25 Australian tax return

• Claim a foreign income tax offset for the $375 USD withheld by the IRS

• Keep the 1099-B, broker statements, and her own acquisition records in case the ATO queries her return

Sarah’s experience is now typical for Australians with US investments. The combination of stricter IRS reporting, ATO data matching, and complex cross-border rules means the 1099-B is a document you can’t afford to ignore.

As US brokers and crypto exchanges ramp up 1099-B issuance in 2026, Australians with global portfolios must be prepared. Understanding how to interpret, reconcile, and report Form 1099-B information is now essential for tax compliance and peace of mind. With the ATO and IRS sharing more data than ever, proactive record-keeping and careful reporting will keep you out of trouble—and help you make the most of your investment returns.