Janus International, the $5 billion global arm of Denver, Colorado-based Janus, a $145 billion mutual funds company, has not had a presence in Asia for long, but reports a brisk business around its expertise in managing American securities. Having established a head office in Hong Kong just two years ago, it is now expanding its business into Taiwan and Korea, as well as bolstering itself as not just a provider to high-net worth clients but also to the mass retail market.