As many as two-fifths of malicious or risky apps on the Google and Apple stores are developed by publishers in the US, according to a report by Marble Security.
The study of one million programs found that those covertly leaking data, sending premium text messages or otherwise abusing the device were more likely to have been built in America than any other country.
David Jevans, chief executive of Marble, wrote on the firm’s blog: "These results surprised me, as I was fully expecting China and Russia to be the largest publishers of malicious and highly risky apps."
"This may be true if you consider non-mainstream app stores, or apps that only run on jailbroken and rooted devices [which can download apps from third-party stores]," he said.
"But this study was to look at the risk to everyday users, consumers and business users, of standard iPhones, iPads, and Android devices."
Other strong producers of malware included China, responsible for 18% of malicious mobile apps on Google and Apple stores, as well as India, Korea and Taiwan, which published 4.5% of bad apps each.
However the report also showed that a higher proportion of all software developed by certain Asian countries was likely to be malicious, with almost 9% of Chinese mobile apps being malevolent, 7% of Taiwanese apps and 4% of Singaporean apps.
"Privacy risks affect not only consumers, but also open enterprises up to Advanced Persistent Threats (APT) and targeted attacks when apps on employee devices leak important enterprise information such as contact databases, browser histories, and app inventories," Jevans added.
