Agencies carry money that is not theirs. Client ad spend on Google and Meta, media buys, supplier costs and licences all flow through the agency's accounts on the way to and from clients. Handled loosely, it distorts your numbers, creates GST headaches and turns month-end into a guessing game. Handled properly, it reconciles cleanly and stays out of the way. This guide is the operational how-to for getting agency pass-through right.
Published: June 2026
Your business might book several hundred thousand dollars a month in ad spend that belongs to clients, not to you. That spend is not your revenue, but if it runs through your books unmanaged, it inflates your reported income, muddies your margin, complicates your GST and makes it hard to see how the agency is actually performing. The fix is to treat pass-through as its own discipline, separate from your fee income, and reconcile it religiously.
The first move is structural: keep client pass-through funds out of your trading accounts.
This separation is what makes everything downstream, GST, reconciliation and reporting, manageable rather than a monthly scramble.
Agencies handle the markup question two ways, and each has a different GST and P&L treatment.
The key point, drawn from the Tax Office guidance, is that the GST treatment follows the substance of who the supply is made to, not whether you itemise the recharge or add a margin. If the ad spend is supplied to you to deliver your service, GST applies on the recharge regardless. We cover the full agent-versus-principal test in our companion guide on accounting for pass-through costs. For most agencies buying media in their own name, principal treatment applies.
This is where pass-through is won or lost. Each period, match the cost to the recharge:
A monthly reconciliation that ties platform spend to client recharges, line by line, is the control that keeps the whole thing honest. Without it, small mismatches compound until you are funding client spend out of your own pocket without realising. Build it into your month-end close as a fixed step, not an afterthought, and keep the working papers so any client query can be answered from the record rather than from memory.
Pass-through is a cash-flow trap as much as an accounting one. You often pay the platform before the client pays you, which means you are funding the float. At agency scale, that float can be substantial. Manage it deliberately:
This is the kind of working-capital exposure that does not show in the P&L but can sink an otherwise profitable agency. Our guide on the five numbers that tell you if a business is heading for trouble is worth a read alongside this.
Because principal pass-through grosses up your revenue, your reported top line can look far larger than the agency you actually run. An agency billing $300,000 a month in media on behalf of clients, at nil margin, is not a $300,000-a-month business; its real revenue is the fees. Keep two numbers in view: gross billings (everything that flows through, including pass-through) and net revenue (your actual fee income). Net revenue is the number that tells you how the agency is performing, and the one that matters for benchmarking, margin and valuation. Confusing the two flatters the business on paper and hides the real picture.
Scale Suite handles agency pass-through, separate-account workflows and monthly reconciliation as part of our finance services, so your real numbers stay clean and your client media stays accounted for.
How should an agency account for client ad spend?
Run it through a separate bank account, invoice it separately, map it to dedicated ledger accounts, and reconcile platform spend to client recharges every month-end. Keep it isolated from your fee income.
Do I charge GST when I recharge ad spend to a client?
If you buy the media in your own name and carry responsibility for it, you are a principal: claim the GST credit on the platform cost and charge GST on the recharge. The treatment follows the substance, not whether you add a margin or itemise it.
Should I mark up ad spend or recharge at cost?
Both are common. At cost, you pass through exactly what you paid at nil margin on that line. With a handling fee, your margin shows as extra revenue. Either way, principal GST treatment usually applies.
Why keep ad spend in a separate bank account?
Because it is client money flowing through your business. Separating it stops it being mistaken for your own cash, makes reconciliation clean, and protects you from spending client float by accident.
What is the difference between gross billings and net revenue for an agency?
Gross billings include everything that flows through, including pass-through media. Net revenue is your actual fee income. Net revenue is the real measure of agency performance; gross billings overstate the business.
How do I avoid funding client ad spend out of my own pocket?
Reconcile monthly so nothing is stranded, watch the timing gap between paying platforms and being paid, and consider pre-funding or shorter terms on pass-through so you are not banking large client media on your balance sheet.
Does separating ad spend on the invoice change the GST?
No. The Tax Office guidance is clear that GST follows the substance of the supply, not the invoice layout. Itemising a recharge separately does not make it GST-free.
Scale Suite is a Sydney-based provider of outsourced finance teams and fractional CFO services for Australian SMEs. We deliver weekly bookkeeping, payroll, BAS/IAS lodgement, cashflow reporting, management accounts, and strategic fractional CFO oversight, all as a fully embedded team that works inside your business.CA-qualified, Xero Certified, and registered BAS Agents, we replace fragmented bookkeepers and once-a-year accountants with one responsive finance function at a fraction of the cost of full-time hires. We serve growing businesses across Sydney, Melbourne, Brisbane, and Perth, with packages starting from $1,500 per month and no lock-in contracts.
We review and check this guide periodically. At the time of writing (June 2026), all information was current. Scale Suite is a registered BAS Agent, not a licensed tax advisor or financial advisor. This content is general information only and does not constitute professional tax, financial, or legal advice. Some details may change over time.
Scale Suite is a Sydney-based provider of outsourced finance and HR services for Australian SMEs. We deliver bookkeeping, financial reporting, payroll processing, fractional CFO support, recruitment, employee onboarding, people and culture support, and fractional HR oversight, all as a fully embedded team that works inside your business.
Employment Hero Gold Partner, CA-qualified, and Xero Certified, we replace fragmented finance and HR processes with one responsive, senior-level function at a fraction of the cost of full-time hires. We serve growing businesses across Sydney, Melbourne, Brisbane, and Perth, with packages starting from $1,500 per month and no lock-in contracts.
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