(Adds background, rivals' share movement)
Nov 20 (Reuters) - Short-seller Citron Research questioned voxeljet AG's quarterly results, saying the Germany-based 3D printer maker provided loans to customers to generate sales and avoid posting a loss in its first results as a public company.
Shares of voxeljet, which went public in a rousing debut last month, plunged as much as 26 percent on Wednesday.
"We're not even sure such sales qualify as revenue ... that would depend on who the parties are and the collectability of the receivables, but why ruin a good bubble," Citron said. (http://link.reuters.com/zec84v)
Voxeljet makes large 3D printers for prototyping and counts Daimler AG, Ford Motor Co and 3M Co as customers. The company's printers were used to make three Aston Martin DB5 model cars for the latest James Bond film, "Skyfall".
Voxeljet, whose rivals include 3D Systems Corp, Stratasys Ltd and ExOne Co, was not immediately available for comment.
Shares of the company, which listed last month at $13, have more than quadrupled since then up to Tuesday's closing. The stock was trading at $42.77 on Wednesday on the New York Stock Exchange.
The cost of 3D printing technology has fallen in recent years, leading to the technology finding new applications in manufacturing, such as prototyping, and the launch of small printers for the consumer market.
U.S. President Barack Obama, in his State of the Union address in February, said 3D printing technology had "the potential to revolutionize the way we make almost everything." (http://link.reuters.com/fuw85t)
But Citron, run by California-based investor and noted short-seller Andrew Left, has called the technology hyped.
In February, Citron accused the chief executive of 3D Systems, the largest listed 3D printer maker, of exaggerating advances in the technology and contributing to a bubble in shares of companies in the sector.
Voxeljet's revenue rose 77 percent to 3.5 million euros ($4.7 million) in the quarter ended Sept. 30. The company reported a profit of 0.11 euros per share.
Voxeljet has a score of just 2 out of 100 on the Thomson Reuters StarMine Relative Valuation model. The lower the score, the more expensive the stock.
Only one of the four analysts covering the stock has a "buy" rating on it, with the rest rating it a "hold".
"VJET is the winner in Wall Street's race to the bottom," Citron said. "It's not even a company, it's just a hobby."
The short-seller set a fair price target of $12.09 on voxeljet's American depositary share.
Short sellers such as Citron make money when the stock price of a company drops. They sell borrowed shares in the hope of buying them back at a lower price and return them to the lender, and gain from the difference in price.
Shares of 3D Systems were down 9 percent, while those of Stratasys fell 6 percent. ExOne shares fell 9 percent. ($1 = 0.74 euros)
(Reporting by Sruthi Ramakrishnan and Chandni Doulatramani in Bangalore; Editing by Kirti Pandey)