A Nobel Prize gold medal awarded to the economist who invented the calculation for the gross domestic product, Simon Kuznets, has been sold at auction here for $390,848.

It was the first gold medal for the Nobel Prize in Economic Sciences - and only the sixth Nobel medal - ever to be sold at auction. It went under the hammer late Thursday at the Nate D. Sanders’ Auctions in Los Angeles. The buyer’s identity was not disclosed.

In December, celebrated American geneticist James Watson sold his Nobel for $4.75 million at auction in New York.

, in the first sale of the prize by a living laureate. Kuznets, who died in 1985, was awarded the prize in 1971 for his research and interpretation of economic growth. He was only the third recipient of the prize.

Unlike his peers, he used demography and statistics to understand the effects of population growth on national productivity. Made of 23-karat gold, the medal features the profile of Swedish chemist and inventor Alfred Nobel. The medal was displayed in its original red leather case with Kuznets’s name gilt-stamped. It also came with a letter of authenticity from the economist’s son Paul.