App marketing company Fiksu said that competition in Apple’s App Store for the iPhone in the US “rose slightly” in June, with the cost to acquire loyal users increasing by 14.3 percent over the previous month.

The Fiksu App Store Competitive Index, which measures the average aggregated daily download of the top 200 free apps in the store, increased by 1.98 percent to 4.63 million daily, “as the anticipated uptick in summer download activity kicked in”.

The company said that the increase in its “Cost per Loyal User Index” followed some companies boosting spend as the second quarter came to an end, as “marketers utilised their remaining budgets”.

“While caution was the keyword for last month’s mobile marketing spends, renewed confidence appears to be June’s theme”, said Micah Adler, CEO of Fiksu.

Fiksu has previously noted an upward trend in app volumes, after a lull in which no events took place to drive downloads – such as a new iOS device launch, or holiday period.

The Cost per Loyal User Index had also been decreasing, as the industry geared-up for the summer.