Trafigura, one of the world's largest and most profitable commodities traders, plans to approach investors next week over its first bond issue, in a move to diversify its funding.

The capital market issue would mark a significant departure for the publicity-shy trader, which has until now relied on bank credit lines. Tapping the bond markets will force Trafigura to open its books for the first time to investors, raising its public exposure.

The trader's financing plans are another sign that the traditionally publicity-shy Switzerland-based trading houses, which dominate global commodities markets, are slowly lifting their veil of secrecy. Glencore, the world's biggest trader, is moving towards a public listing, while oil traders such as Vitol or Gunvor have disclosed some financial details.