Advertising efficiency deteriorated sharply by Q2 2026. Early quarters showed strong conversion growth against flat costs, but Q2 saw conversions plummet, with Search dropping roughly 38% and Shopping falling nearly 28% year-over-year. Because costs remained slightly positive, overall profitability is severely strained. Meanwhile, mobile continues to heavily dominate both conversions and costs for Shopping and Performance Max campaigns.
The annual trajectory reveals a classic Q4 holiday surge, but exposes a critical efficiency gap: peak-season costs spiked significantly sharper than conversions. This indicates aggressive, lower-ROI bidding during high-competition periods. Post-holiday, costs remained “sticky” while conversions normalized, steadily eroding baseline efficiency into the spring.
While the line chart shows expected seasonality, YoY data exposes a volatile efficiency narrative. Q3 through Q1 delivered exceptional ROI, with Shopping and Performance Max (PMax) driving massive conversion growth on nearly flat YoY costs. However, Q2 reveals a severe market correction: conversions plummeted across all channels (Search dropped ~40%) despite costs remaining flat or slightly elevated. This signals a sudden, drastic spike in Cost Per Acquisition (CPA).
The Q2 conversion crash, coupled with flat costs, points to macroeconomic headwinds—such as consumer spending fatigue—colliding with automated bidding systems that stubbornly maintain spend targets despite declining user intent. Furthermore, the shift away from Search toward PMax aligns with platform-wide pushes toward broad match and AI-driven placements. These automated systems excel at capturing cheaper, top-of-funnel mobile conversions during growth periods, but struggle to maintain efficiency when overall market demand abruptly contracts.