Grupo Mexico SAB, the country’s largest mining company, announced that it increased the most in just four months of period after fourth-quarter sales at the United States based unit doubled up on increasing copper costs and output.

The Mexico City-based company has raised 7.1% to 28.39 pesos in Mexico trading, the sharpest gain since September 22.

According to the statement issued by Southern Copper Corp., a Phoenix-based unit of Grupo Mexico, “fourth-quarter sales more than doubled to $1.14 billion.”

Moreover, the net income was 43 cents per share, more than the average figure of 32 cents from six analysts studied by Bloomberg.

While talking to reporters, an analyst of BBAV Bancomer SA, Pablo Abraham said, “Southern Copper’s fourth quarter was very good.”

Further, Pablo said, “If their earnings were good, obviously Grupo Mexico will have good earnings, too.”

Moreover, Abraham told reporters that the Southern Copper accounts for as much as 80 percent of Grupo Mexico’s revenue.