Budget Capped Mid-Month on a Profitable Campaign
A Sponsored Products campaign for a $45 product hits its $50/day budget by 11 a.m. every day. It runs at 15% ACOS against a 25% target, with a 12% conversion rate and a $0.90 average CPC. The advertiser has $3,000/month total ad budget across three campaigns. The other two campaigns run at 30% and 35% ACOS and never hit their budgets. The advertiser is considering raising this campaign's daily budget to $150/day to capture the lost impressions. Monthly sales from this campaign are currently ~$10,000.
1. Quantify the opportunity and the risk of raising the budget to $150/day.
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Current state: $50/day cap, hit by 11 a.m. → roughly 4-5 hours of the day captured. At $0.90 CPC and 12% CVR, each $1 of spend returns ~$45 × 0.12 / $0.90 ≈ $6 in sales per $1 spent (≈15% ACOS). Monthly spend ≈ $1,500, sales ≈ $10,000 - consistent.
Opportunity: Raising to $150/day triples the cap. If the same efficiency held, spend would rise ~$3,000/month and sales ~$20,000. But that is the trap: the campaign is budget-capped because it is winning the cheapest, highest-converting auctions first. The next $100/day of impressions will be lower quality - later-day, lower-intent, more expensive. Expect ACOS to rise, not stay at 15%.
Risk: $3,000/month is the entire account budget. Moving to $150/day on one campaign consumes ~$4,500/month - more than the total budget. The other two campaigns ($30-35% ACOS) would be starved. Blended ACOS would likely worsen even as the hero campaign's ACOS drifts up.
So a naive 3x is both unaffordable and likely to degrade efficiency.
2. Design a budget reallocation and testing plan that captures the upside within the $3,000 cap.
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Step 1 - Fund the winner from the losers. The 30% and 35% ACOS campaigns are above the 25% target and never spend their full budget. Cut them to maintenance levels (e.g., $15/day each) and redirect to the hero campaign. New split: hero ~$70/day, others ~$15/day each ≈ $3,000/month.
Step 2 - Raise the hero cap incrementally, not 3x. Go $50 → $70/day for 7-10 days. Watch ACOS and the hour-of-day the cap is hit and the search term report for new low-quality terms. If ACOS holds ≤20%, step to $90/day. Stop when marginal ACOS crosses ~25% - that is the true efficient frontier.
Step 3 - Protect efficiency as you scale. Add negatives for any new zero-conversion terms that appear with the extra spend. Consider a dayparting adjustment if the incremental spend is concentrated in poor-converting hours (where supported), or lower the bid slightly to stretch the budget across the day.
Step 4 - Harvest. Move top converting search terms into a dedicated exact-match campaign so the hero campaign keeps discovering while a controlled campaign captures the proven demand.
Success metric: incremental sales per incremental dollar. Track ACOS by spend tier - the first $50/day vs. the next $20/day - to see the marginal efficiency directly.