Osman Semerci, Merrill Lynch’s former global head of fixed income, currencies and commodities, and co-president of the EMEA global markets and investment banking business, has joined $1.7 billion alternatives group Duet as its chief executive. Duet Group, which started in 2002 with just $10 million in a single fund, now has 14 funds, and is looking to further expand its range of strategies, in addition to growing its private equity business.