During the fourth quarter of last year, the Gigafactory added 832 employees and $459 million in capital investment.
That brought total employment to 3,249 and total capital investment to $3.7 billion. That's more than the $3.5 billion minimum capital investment benchmark officials set in 2014.
The capital spending plus another $402 million the company reported spending during the first half of this year means construction investment at the Gigafactory has surpassed $4 billion.
Tesla says that by surpassing a 20 gigawatt hour annualized run rate in July it became the largest battery factory in the world, "by a significant margin."
The 2018 spending also suggests employment at the Gigafactory has continued to increase significantly since the end of the reporting period for the latest state audit.
In addition to capital investment and full-time employees, the Gigafactory employed 1,332 construction workers in the fourth quarter, bringing total construction worker employment to 13,743.
The average hourly wage of full-time employees for the project is $34.97, higher than the $22 per hour officials set as a benchmark in 2014.
Paul Anderson, executive director for the Office of Economic Development, praised Tesla for hitting benchmarks and for its other investments in Nevada, such as a pledge to spend tens of millions of dollars for science and robotics programs in Nevada schools.
"Tesla is an outstanding partner for Nevada, from surpassing their performance benchmarks at the Gigafactory to their $37.5-million pledge in support of science and robotics programs at our schools, they've done everything they said they would do and more," Anderson said. "We're very proud to have Tesla as a member of the Nevada family."