Production delays hit quarterly earnings for two of the three 3D printer makers that have already reported third-quarter earnings. Even Stratasys Ltd. (NASDAQ: SSYS), the one 3D printer maker that beat estimates, hasn’t been able to overcome the jitters investors have felt about the sector.

Both Hewlett-Packard Co. (NYSE: HPQ) and General Electric Co. (NYSE: GE) have indicated that they will enter the 3D printing — or as some call it, additive manufacturing — sector. GE expects to spend $32 million over the next 3 years on a facility near Pittsburgh to develop and implement 3D printing technologies. HP is expected to release its first product in 2016.

The existing companies have some time to work with, but investors may be questioning if they know what to do with it. Since the beginning of November, shares of Stratasys have lost nearly 16%. Competitors The ExOne Co. (NASDAQ: XONE) and 3D Systems Corp. (NYSE: DDD) are down 16.6% and 12%, respectively. Over the past 12 months, Stratasys is down about 19%, 3D Systems is down more than 57% and ExOne is down about 65%.

After markets close Thursday, a fourth player, Voxeljet A.G. (NYSE: VJET) reports third-quarter results and is expected to post a per share loss of $0.04 on revenues of $4.59 million. In the same period a year ago, Voxeljet posted per-share earnings of $0.02 on revenues of $3.52 million.

In the latest reporting period, through October 31, short interest dropped in both ExOne and Voxeljet, though ExOne’s short interest remains at 48.6% of the company’s float. Voxeljet’s shares also trade on the XETRA.

Short interest in both Stratasys and 3D Systems grew, and 35% of 3D Systems’s stock is now short, as is 14.4% of Statasys’s.

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