Rolling Stone has sold a 49 per cent stake to BandLab Technologies, a Singapore-based music start-up founded by one of the richest families in Asia. The partnership with BandLab is part of an effort to diversify Rolling Stone’s revenues as the 48-year-old magazine, a stalwart of US pop culture, grapples with the industry-wide shift to digital. The companies will form an international Rolling Stone subsidiary based in Singapore, focused on live events and marketing services, and aim to bulk up the magazine’s reach globally.