The Paid Traffic Truth : The 159% Markup Hiding Inside Your Blended CAC

01 / Introduction

The two CACs, revisited 

Every week we aggregate first-party, order-verified data across hundreds of eCommerce accounts and publish the four grids: new customer acquisition, first click versus last click, overall channel performance, and new customer lifetime value. One story per issue. This week the story is the markup between aCAC, the blended cost of acquiring any customer, and nCAC, the cost of acquiring a customer who has never bought from you before.

We ran this comparison in our very first issue. I am running it again on purpose, because the honest news is persistence. This is not a weekly anomaly you can wait out. It is a structural property of how blended CAC is calculated, and the size of the distortion depends entirely on which channel you are looking at.

02 / Analysis 

Every channel marks up its blended CAC. Not equally. 

The mechanism is simple. Blended CAC divides spend by all customers acquired, new and repeat alike. Repeat buyers convert cheaply because they already know you, so every repeat purchase mixed into the denominator pulls the average down. The more a channel leans on people who have already bought, the more flattering its blended CAC looks, and the bigger the surprise when you isolate true new customers. 

Look at the shape of that chart. Meta's line is barely visible, a 14% markup, because 87% of Meta's tracked buyers this week were genuinely new. Meta's blended number and its new customer number are nearly the same number. Google marks up 51% at 66% new. Microsoft marks up 67% at 60% new. Then there is YouTube, where only 39% of buyers were new, and the markup explodes to 159%. The rule holds across the whole grid: the lower a channel's share of new buyers, the bigger the lie in its blended CAC.

One honest note on this week's magnitude. The markup pattern itself is structural. It comes from arithmetic and channel mix, not from the calendar, and it will look similar next week and the week after. But YouTube's specific 159% figure is elevated this week because YouTube's new visit to customer conversion dropped sharply week over week, which pushed its nCAC up hard while blended CAC moved less. Late August is a quiet stretch with no holiday selling event to blame, so read the direction as permanent and this week's YouTube extreme as the high end of its normal range. And because this data blends hundreds of accounts, no single brand's promotion can move these aggregates.

03 / New Customer Acquisition 

The full acquisition picture, by channel

Meta keeps its spot as the volume engine, and at 87% new it is doing the job most brands assume all their paid channels are doing: bringing in people who have never bought. Google converts steadily at a defensible $154 nCAC. The row to sit with is YouTube. Only 39% of its buyers were new, its conversion rate fell by half week over week, and its nCAC landed at $826. If your dashboard shows YouTube at its blended $319, you are looking at a number that is mostly repeat purchase behavior wearing a prospecting costume. 

04 / First Click vs Last Click 

Who starts the sale vs who takes the bow

Same pattern as always: the social and video channels that open relationships get shortchanged by last click, and the search channels that close them get inflated. Notice this cuts the opposite way from the markup story. Last click makes YouTube look slightly worse than it is on revenue credit, while blended CAC makes it look wildly better than it is on new customer cost. Two different distortions, one channel, and neither one visible if you only run one report.  

05 / Overall Channel Performance

Where the money goes, and THE TRUE COST OF A NEW CUSTOMER 

Read the markup column top to bottom. Every single paid channel costs more per new customer than its blended CAC admits. There is no channel where the blended number is honest. The only question is how big the markup is, and the answer ranges from a rounding error on Meta to more than double on YouTube. If your growth model uses one CAC for the whole business, your model is built on the most flattering version of every channel simultaneously.  

06 / New Customer Lifetime Value

What a new customer becomes over a year

Here is the fairness clause for YouTube. Its new customers start small at $84 and nearly triple to $244 by one year, still the steepest growth curve in the set, a pattern we covered in depth in Issue 008. That back-end value is real, but it does not erase an $826 nCAC. It means YouTube is a channel you evaluate on a payback window, not on week-one math, and definitely not on blended CAC. One caveat that applies to this whole grid: it blends brands at very different price points, so treat it as a directional market benchmark, not a promise for your store.  

07 / Conclusion 

One business, two CACs. Budget off the right one. 

The blended CAC on your dashboard is answering a question you did not ask. You want to know what growth costs. It is telling you what activity costs, with your cheapest, most loyal buyers averaged in to make every channel look better than it is. Nine issues into this series, the markup between the two numbers has shown up every single week, on every paid channel, without exception.

The fix is not more reporting. It is verifying new versus repeat at the order level, pricing each channel by its true nCAC, and then making Scale, Chill, or Kill decisions off that number. Meta at a $88 nCAC and 87% new is a different decision than YouTube at $826 and 39% new, even though blended CAC says they are $77 and $319. Know which number you are looking at before you move the budget.

How this week's numbers were built. Aggregated across hundreds of Wicked Reports client accounts for the week of August 23 to August 29, 2026, except first click vs last click, which uses a rolling 90 day window. New versus repeat is verified at the order level against first party order IDs, not modeled and not surveyed. The new visit to new customer conversion rate credits the channel that originated the new visit. Channels without cost data, including email, SMS, organic, and influencer, are left out of the cost comparisons. Snapchat is excluded for negligible spend. Pinterest is marked with an asterisk because it ran on a small number of new customers this week, so it is not used to anchor any headline. The channel labeled Facebook in the underlying platform data is shown here as Meta. Charts and tables carry meaning through direction, labels, and contrast rather than color alone.