On July 14, 2026, the Hong Kong Inland Revenue Department issued its latest circular to tax representatives: The deadline for paper tax returns for Category D companies has been extended to August 31, and the deadline for electronic filing has been extended to October 2. That is exactly 10 days from today.

Cross-border e-commerce businesses and foreign trade companies most commonly use Category D Hong Kong companies with a December fiscal year-end. This extension directly affects the annual compliance schedules of thousands of sellers in Shenzhen, Guangzhou, Dongguan, and Foshan.

Ten days—it doesn’t sound like a short time. But when you break it down—sorting out related-party transactions, preparing audit reports, compiling transfer pricing documentation, and gathering evidence to substantiate the business substance—if any one of these steps gets held up, the deadline becomes the end of the road.

💡 If your Hong Kong company has a December fiscal year-end, has not yet started the audit for the 2025/26 tax year, or if you’re unsure whether you fall under Category D, add Qicaiying Customer Service on WeChat: qcygscszk, or call 18676749275, to receive a one-on-one assessment of your tax filing status and filing window.

Last week, Mr. Wang, who runs a German-focused online store in Shenzhen, was still feeling confident: his store’s annual sales were in the millions of euros, and he’d already obtained his LUCID registration number—so he thought he was in the clear. But when he checked, he found that his number was registered under the old Packaging Act (VerpackG) system in 2024, and the rules will change completely after August 12, 2026.

I’m sure many business owners on Meike Duo focus their efforts on running their stores and overlook the issue of tax filing. One of Qicaiying’s clients has been operating a local store in Mexico for a year. We’ll call him Mr. Sun. Throughout that year, he believed he was fully compliant—he filed his taxes on time every month based on 3% of his GMV, paid every penny he owed, and had no overdue records in the SAT system. He thought that 3% covered all his tax obligations, and once he paid it, he felt at ease. That is, until early the following year, when his accountant helped him with his annual tax settlement and informed him: “The monthly 3% payments are merely advance payments. The annual ISR is calculated based on actual profits, with an effective tax rate ranging from 29% to 35%. Since you’ve made a decent profit this year, you’ll need to pay the difference.”

President Sun was baffled: “I thought 3% was the total amount. Why do I have to pay such a large sum again at the end of the year?”

Monthly 3% and annual back payments—this “dual-track system” is a pitfall that many cross-border sellers in Mexico’s RFC tax ID system tend to overlook. It’s not that they fail to file; rather, they don’t realize that the “3% filed monthly” does not equal the “total tax owed for the year.”

There’s one thing that owners of U.S.-based online stores tend to overlook: sales tax isn’t a federal tax—it’s a state tax. Each state sets its own rules, and those rules change every year. In 2026, several more states changed their thresholds, leading to more people falling into these traps than in previous years. This article avoids technical jargon and simply explains: in which states you actually have to pay sales tax, how to pay it, and which payments are most likely to be overlooked.

Owners of Douyin and Taobao stores have recently been asking the same question: Has the fixed-rate taxation system been eliminated, and will all businesses now be subject to audit-based taxation? The answer isn’t that straightforward, but regulations have indeed tightened in 2026, with e-commerce businesses being the primary focus. Today, we’ll thoroughly explain the differences between ”audit-based taxation” and ”fixed-rate taxation” so you’ll know exactly how to pay your taxes and which tax incentives you can still take advantage of.