Before we count down the last few days of summer, we looked back on August CPI data. Last year we saw a decrease in CPIs from July 2013 to August 2013, but that wasn?t the case this year. Despite students going back to school, it seems like advertisers didn?t think user LTVs would go down too much to warrant lowering their advertising bids. Average bids on iOS were up 13.8%, down -0.8% on Google Play, and up 1.5% on Amazon.

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iOS Exhibits Consistent CPI Growth Across All Device Types

Summary

• iPad: CPI up to $3.04 (+13.3%)
• iPhone: CPI up to $2.56 (+13%)
• iPod touch: CPI up to $1.64 (+13.5%)

August was a strong month for iOS, as it displayed consistent growth across all device types. Normally, we see differences in growth between iPad and the other two device types -- iPhone and iPod touch.

Clearly, advertisers are both valuing iOS users more than ever, and on each iOS device type. Come back next month to see if iOS sustains its CPI levels in September. Also, in preparation for the impending launch of the iPhone 6 on September 19, we dug into August iPhone CPI data, gathering the top 10 CPI growth countries and the top 10 CPI loss countries (above).

Google Play CPI Swells in South Korea

Summary

• Google Play: CPI down to $1.20 (-0.8%)

Google Play CPIs showed marginal change in August, but we did notice interesting trends in East Asian countries. We saw average CPIs in South Korea jolt upward by 55%, while simultaneously CPIs dipped -19% in Taiwan and -22% in Hong Kong. With the impending release of the Samsung Galaxy Note 4 (with Gear VR capability) and the Samsung Galaxy Note Edge, it seems like advertisers are preparing for a new set of devices to come rolling in from the South Korean market.

Release of Amazon Fire Phone Has Little Effect on Amazon CPI

Summary

• Amazon CPI: CPI up to $2.03 (+1.5%)

We were looking forward to seeing the effects of the release of the Amazon Fire Phone, but according to The Guardian, it seems like Amazon had only sold an estimated 35,000 units. With only two months under its belt, it isn't surprising that the Fire Phone had little effect on the average Amazon CPI bid in all the larger countries.With Apple revealing the iPhone 6 on Tuesday, it?s entirely possible that average iOS CPIs in September will continue to grow as users upgrade to the new iPhones. Additionally, we saw that Amazon recently lowered their Amazon Fire Phone price to $0.99, which gives an entirely new level of incentive for users to switch over to these relatively new devices. Keep it locked to the Chartboost Blog for the next Top CPI report and much more.Chartboost CPI InsightsCheck out CPI trends for more countries on Chartboost Insights.The shared CPI figures are averages from our Network and should be used for guidance only.