Building a daily P&L

A profit and loss statement, or P&L, is a list of what came in, what went out and what is left. Large companies produce one a quarter. An arbitrage operator needs one every day, because the business can turn from profit to loss overnight and the only defence is noticing quickly. This lesson builds one from scratch using everything covered so far.

A market trader counts the cash box every evening. Not because the taxman asks, but because tomorrow's order of stock depends on knowing what today really made. A trader who counted once a month would discover a bad pitch four weeks too late.

The five lines

1. Ad spendWhat each traffic source charged for the day, per campaign. Take it from the ad platform itself, in the same time zone as revenue. This is your traffic acquisition cost.
2. Estimated revenueWhat the feed reports for the same campaigns, matched through Channel ID or tracker data. If the provider shows revenue before its own share, use the figure after revenue share: your net revenue, not the gross revenue.
3. Clawback reserveA percentage taken off estimated revenue to allow for deductions at finalisation. Use your own measured rate plus a safety margin.
4. Direct costsCosts that exist because of the campaigns: tracker, hosting, content and creative production, financing fees.
5. OverheadsSalaries, software, accounting, office. Spread them evenly across the days of the month.

A worked day

Here is an illustrative day for a small operation with three campaigns.

The dashboard says the day made $80. Now add the lines the dashboard leaves out. Suppose this operator's history shows about 5% of estimated revenue is lost at finalisation, and the daily share of tools, content and other overheads comes to $20.

Reading the sheet by campaign

The total hides three different stories. Apply the same 5% reserve to each campaign. Campaign A: $520 becomes $494, a contribution of $94 on $400. Campaign B: $310 becomes $294.50, a loss of $5.50 on $300. Campaign C: $150 becomes $142.50, a loss of $57.50 on $200. One campaign carries the business, one that looked marginally positive is in fact negative, and one is plainly losing.

Stopping C alone would lift the day's contribution from $31 to $88.50. But note what it leaves: a business where one campaign on one ad account supplies all the profit. That is concentration risk in a single row. A good P&L shows both the money and the dependence.

Three versions of the truth

Each month, go back and replace estimates with finalised figures. This true-up does two jobs. It shows the real profit, and it tells you whether your reserve was too small. If finalised revenue came in 8% under estimate while you reserved 5%, raise the reserve and look for the source of the extra loss. Then keep the month open in your mind: later deductions can still arrive, as the lesson on clawbacks explained.

1. Money goes out first: Through March the arbitrageur buys 100,000 visitors at $0.20 each. The ad platform bills its card every few days: $20,000 of ad spend is gone before any income arrives. (An illustrative month.)
2. The dashboard shows an estimate: Each day the feed reports estimated revenue. By month end it reads $28,000, a paper profit of $8,000. It is a running tally, like a restaurant bill before the manager checks it.
3. The engine reviews the clicks: After the month closes, the search engine’s systems finish checking for invalid clicks: bots, accidental taps, repeated clicks, traffic that broke policy. The publisher does not get an itemised list of what was removed.
4. Advertisers are credited: Clicks judged invalid are credited back to the advertisers who paid for them. Say that comes to 5% of this publisher’s clicks. Nobody in the chain earns anything on a refunded click.
5. The clawback: 5% of $28,000 is $1,400, deducted from the publisher: a Clawback (revenue deduction). The $20,000 spent buying those visitors is not refunded by anyone. A heavy clawback can turn a profitable month into a loss after the fact.
6. Revenue is finalised: $28,000 minus $1,400 gives finalised revenue of $26,600. Real profit is $6,600, not $8,000. Google’s own AdSense timeline posts finalised earnings around the 3rd of the following month; feed providers set their own dates.
7. Payment arrives on Net terms: The provider pays on Net terms, here Net 30: about 30 days after month end. Money spent on 1 March comes back around 30 April. Some contracts are Net 45 or Net 60.
8. Growth eats cash: By the time March is paid, April’s $20,000 has also been spent. This cash-flow float means a growing arbitrageur needs working capital of one to two months’ spend, and a late payout or large clawback can sink a business that looks profitable.

Good habits for the sheet

• One time zone. Convert spend and revenue to the same clock before subtracting.
• One currency. If you pay in pounds and earn in dollars, record the exchange rate used. Currency moves can exceed the margin.
• Include failed tests. Money spent on campaigns that never worked is a cost of the business. Leaving tests out makes the survivors look better than the operation is.
• Add a cash line. Under the profit figure, show money owed by feeds, money owed to card issuers or lenders, and cash in the bank.
• Automate the pull, review by hand. Let the tracker and reporting APIs fill in the numbers. A person should still read the sheet every morning.
• Write down why. A one-line note beside each large change builds the history that later explains seasonality and platform shifts.