Hana Shinkumi Bank cuts CPA 74% and drives 19x more applications with unique Amazon signals

Goals

For Hana Shinkumi Bank, a financial services institution in Japan, growth meant reaching new customers ready to open accounts. But as customer acquisition costs rose across their existing channels, the path forwards became less clear. The bank had been running campaigns across six established channels, yet new-account growth had stalled. An outsourced demand-side platform (DSP) campaign, managed by a separate agency, was returning zero applications despite significant investment. The bank needed a new approach.

Unlike brands that sell products on Amazon, Hana Shinkumi Bank is a non-endemic advertiser, meaning they had no direct purchase signals to draw from within the Amazon store. The conventional response would have been to reallocate budget to a proven channel. Instead, the bank’s agency partner Yomiuri Ars A proposed a different path: Amazon DSP. The hypothesis was that Amazon’s purchase behaviour signals could identify audiences with financial intent, even for a brand without products listed on Amazon. To bring this vision to life, the agency partnered with tech partner Shirofune, whose real-time cross-channel analysis and automation capabilities would provide the operational infrastructure needed to act on insights at speed.

Approach

Yomiuri Ars A and Shirofune launched the Amazon DSP campaign in September 2025, starting small with category and contextual signals. Initial results confirmed the challenge: October closed with zero conversions. The breakthrough came through a novel innovation the partners called ‘Search-to-Amazon Standard Identification Number (ASIN) Translation’. Shirofune’s automation platform scanned daily search query performance across Google, Yahoo and Microsoft, surfacing users showing financial intent. The agency identified these audiences on Amazon through their purchases of finance-related products like investment books and planning guides.

The agency translated this demand into specific ASIN selections within Amazon DSP, reaching high-intent users through purchase behaviour signals rather than search intent alone – a first-of-its-kind approach for a non-endemic financial advertiser. The collaboration operated on a daily-to-weekly cycle: Shirofune provided automated cross-channel analysis each day, the agency identified patterns and translated demand into audience design, and biweekly reviews assessed results and set direction for the next cycle. Creative remained unchanged; the ASIN selection strategy alone transformed performance.

Results

From November 2025 until March 2026, the Amazon DSP campaign delivered results that outperformed not just the weakest channel, but the entire six-channel mix. The campaign achieved a cost per acquisition that was 74% below the six-channel blended average and 84% below the original baseline.¹ In total, the campaign generated bank account applications that were 19 times the original benchmark.² The conversion rate more than doubled the blended average.³

Following these results, the advertiser moved from fixed budget allocation to performance-based allocation. Amazon DSP’s share of wallet grew from 0% to 2.3% during the fixed period, then jumped to 7% in April 2026 and 14% in May 2026.⁴ The bank is now adopting Amazon Marketing Cloud (AMC) to build custom audience segments and deepen their understanding of the full customer journey, extending the partnership’s impact beyond media buying into measurement and insights.

This success demonstrates how Amazon’s unique purchase behaviour signals can unlock growth opportunities beyond traditional advertising channels, even for non-endemic advertisers. By combining Amazon DSP’s audience capabilities with partner expertise, brands in any category can reach high-intent customers at scale – across Amazon and beyond.

Sources

^1–4 Hana Shinkumi Bank, Japan, 2025–2026.