24/7 Wall St.

We have tracked the key short interest changes as of July 15 in the following 3D printer and services companies: 3D Systems Inc. (NYSE: DDD), Stratasys Ltd. (NASDAQ: SSYS), The ExOne Co. (NASDAQ: XONE) and Proto Labs Inc. (NYSE: PRLB).

Short interest in 3D Systems rose 0.5% to 27.04 million shares. Some 28.8% of the company’s stock is short.

Short interest in Proto Labs rose 16.8% to 3.05 million shares, or 16.8% of the company’s float.

Stratasys saw short interest rise by 4% in the first two weeks of July to 3.58 million shares, or about 13% of the company’s float.

Short interest in ExOne fell by 7.8% to 2.15 million shares. About 31.8% of the company’s shares are now held short.

Shorts continue to target Proto Labs in the 3D sector because the company is a service provider only. Because the other 3D printer makers also sell equipment as well as services, Proto Labs is seen to be at a disadvantage.

3D printer stocks are still trading near year-to-date highs, with all but Stratasys posting double-digit gains. However, because the technology is relatively new, it is difficult to tell whether stocks are at a peak and have no place to go but down, or if they are about to sprout wings and soar. It is a wait-and-see-what-happens-next game for now.