Because you're paying to re-acquire customers you already own.
This isn't an error on your part; it's a hidden behavior of Meta's algorithm, which is highly effective at taking the easiest win. For a platform, a cheap conversion from a warm, existing audience is a win. For your balance sheet, it's a 20–40% overspend on recycled revenue. We consistently see this pattern across 2,000+ eCommerce brands we analyze.
This Meta behavior creates four painful outcomes for your business:
Warm audiences—existing customers, high engagers, email lists—provide cheap conversions. Meta's system prioritizes these pockets, leading to a high reported ROAS. This false confidence encourages you to scale a campaign that primarily hits repeat-heavy segments, masking the failure to acquire new, sustainable growth.
Your "Prospecting" or "Top-of-Funnel" campaigns are meant to find net-new customers. However, the algorithm quietly shifts spend toward people who are just slightly outside the retargeting window, or who have already purchased but are technically still "prospects" based on Meta's limited data set. The result: Prospecting spend rises, ROAS climbs slightly, but your genuine New Customer acquisition flattens.
Meta's Automated Shopping Campaigns (ASC) are designed for efficiency, and efficiency means taking the easiest path to conversion. Without an external, reliable signal of who is truly "New," ASC will increasingly shift budget toward repeat-heavy pockets to maintain a high reported ROAS, accelerating the cycle of overspending on existing buyers.
This is the ultimate business killer. When 20–40% of your budget is dedicated to repeat buyers, the small portion left for genuine new customer acquisition must carry the true cost burden. Your nCAC rises without explanation, and you lose confidence in the exact moment you should be scaling.
You can't fix what you can't see, and you can't tell Meta to stop prioritizing repeat buyers—you must show them.
We built Advanced Signal to fix this. It turns on a reliable, non-Meta source of truth, sending true New Customer Purchase Events back to the platform. By feeding the algorithm accurate data, Meta naturally and automatically shifts its spend allocation toward finding genuinely new buyers.
This is the single fastest, most scalable, and predictable way to lower your nCAC and reclaim the 20–40% of your budget currently being wasted.
👉 See the Damage in Your Data: Join Melissa for a quick, no-pressure data review. She can pull up your numbers and show you the exact percentage of your budget currently being recycled.
FAQ
This means that a significant portion of your ad budget (often 20–40%) is being spent on campaigns that primarily serve ads and generate purchases from customers who have already purchased from your store. Meta's algorithm finds these people "easy" to convert, leading to high platform ROAS, but it's fundamentally a waste of budget that should be targeting net-new customers.
Advanced Signal works by sending true, reliable New Customer Purchase Events directly to Meta's system. Traditional tracking often struggles to differentiate between a new buyer and a repeat buyer. By providing this accurate signal, we train the Meta algorithm to shift its targeting and optimization away from the easily converted repeat buyers and toward audiences that are genuinely new, resulting in a predictable reduction in your New Customer CAC (nCAC).
This happens because Meta's algorithm is trained to maximize platform efficiency and reported ROAS, which often means prioritizing the easiest conversions. Even in Prospecting, the algorithm may target audiences that are highly familiar with your brand or customers just outside the typical retargeting window. Without a clear New Customer signal, the algorithm has no incentive to stop, causing prospecting success to flatten while your overall nCAC rises.