Mining giant Glencore Xstrata plunged deep into the red in 2013 with a net loss of $7.4 billion (5.3 billion euros) from a profit of $1 billion a year ago, after booking massive writedowns related to its merger. The group said in an earnings statement Tuesday it took a charge of $7.5 billion during the year to write down goodwill or intangible assets that were now valued at a lower rate than when they changed hands. The impairment charge also included write-downs at various sites amid the "persistent challenging nickel and aluminium market environments". Swiss commodities trader Glencore and mining giant Xstrata merged on May 2, a transaction that propelled it to become one of the world's biggest players in the commodities market alongside firms like Brazil's Vale, British-Australian BHP Billiton and British-Australian Rio Tinto. But just three months after, it booked massive merger writedowns. Revenues for the year however, rose by 9 percent to $232.6 billion, the group said in a statement.