Glencore warned of "continued volatility" in commodities markets as it unveiled a 43% slump in annual earnings, in a statement which again raised the possibility of a stockmarket flotation.

The commodities trading giant said that, while many stimulants behind last year's commodity markets revival should continue to weave their influence this year, it was "mindful of the ongoing reporting of mixed economic data".

With some economies struggling to put the global recession behind them, markets were "in all likelihood" set to remain volatile, Glencore said.

The comments follow statistics questioning the strength of revivals in the US and, in particular, Europe, which recorded economic growth of 0.1% for the last three months of 2009.

They also appear a fillip to CME Group, the group behind the Chicago futures markets, which last week unveiled plans to launch volatility indices for contracts such as corn and crude oil.

'Credible' results 

Glencore said it was thus far into 2010 trading "meaningfully ahead" of the same period a year before, a spell which was characterised by "a recessionary and low commodity price environment".

Revenues fell 30% to $106.4bn in 2009, with earnings tumbling 43% to 2.72bn, excluding one-off charges.

However, the decline concealed a steady improvement in profits in each successive quarter, the company said, terming its results "credible" given the weak economic conditions.

Comparison with earlier statement implies that the pace of Glencore's earnings decline eased to 24% in the last six months of 2009, on revenues down 7.5%.

Flotation ahead? 

The statement also restated a rare mention of the possibility for a stockmarket flotation, or IPO, in relation to an offer in December of $2bn in convertible bonds, which might be turned into Glencore shares.

"Investors have the option to convert the bonds into Glencore shares upon IPO or other pre-determined events," the Swiss-based group said.

The potential for a Glencore flotation has been the subject of lingering speculation since the famously secretive group was reported last year to have held talks with bankers over a listing.