Following $2.6 billion in write-downs in their aluminum, nickel and platinum units, Swiss commodities giant Glencore plc and Xstrata plc announced major 2012 losses while awaiting Chinese regulatory approval for their $36 billion merger.

Glencore officials reported net income fell 75% to $1 billion in 2012, down from $4 billion the year before, while the world’s biggest commodities trader also posted $1.6 billion in impairments. Similarly Xstrata, the world’s number four mining company, recorded a 2012 net income decrease of 79% to $1.18 billion, following $978 million in write-downs.

“The impact of falling commodity prices, inflationary pressure on operating costs, and strong currencies relative to the U.S. dollar put pressure on our margins,” Xstrata CEO Mick Davis said in a statement, adding that growth in China and the U.S. will buffet commodity demand in 2013. The Swiss-based Xstrata also reported a 37% decrease in profits in 2012 from $3.65 billion in 2011.

The merger has witnessed several delays since it was first announced in 2011, though the latest official date is set for April 16. With a market capitalization of $70 billion, the newly combined company will enjoy revenues of more than $140 billion with up to 80% of sales based on mining.