Total consumer and advertiser expenditure on handset-based mobile media, which includes mobile internet, mobile social networking, games, applications, music, video, ringback tones, media alerts, and associated spend on mobile data, will increase from $300 Billion at the end of 2015 to approach $425 Billion by 2021. Across this period, mobile advertising will account for an increasing share of total spend on mobile media, although mobile operators will remain the primary beneficiaries as mobile data use also rises. This report provides an overview of our forecast update and highlights key dynamics impacting the growth of the global mobile media economy.