IBM stock is down following news that one of its top competitors in the quantum computing space, Amazon, is laying the groundwork for a quantum computer of its own.

According to Bloomberg, Amazon has been hiring for a Quantum Hardware Team within its Amazon WebServices Center for Quantum Computing, based on internal job postings on LinkedIn. Marc Runyan, a former engineer with NASA’s Jet Propulsion Laboratory, lists his title as senior quantum research scientist at Amazon and describes his role as “helping to design and build a quantum computer for Amazon Web Services.”

A person briefed on Amazon’s plans told Bloomberg the company is using a superconductor model, a similar approach to that used by Google and IBM, among others. The person said Amazon has been on a hiring spree to staff its quantum computing group.

Of course, “laying the groundwork” for a computer is different from actually building one, and that’s where IBM still dominates, although judging by the stock reaction investors are a little nervous that what until recently was a market dominated by IBM’s machine may soon see competition. Even so, while Amazon is only just now entering the space, IBM already has plans for a 1,000 qubit quantum computer by 2023, a lead which even Jeff Bezos’ billions will find difficult to catch up to.

As Bloomberg adds, among Amazon’s recent hires are research scientists focusing on designing a new superconducting quantum device as well as device fabrication. Developing its own quantum computer would let Amazon more closely mirror the approach taken by its major cloud rivals. International Business Machines first made a quantum computer available to the public in 2016 and has rolled out regular upgrades.

Last year, Alphabet Inc.’s Google said it had built a computer that’s reached “quantum supremacy,” performing a computation in 200 seconds that would take the fastest supercomputers about 10,000 years. But with the rivalrous spirit that has characterized the race to build a quantum computer, IBM cast doubt on Google’s claim. In a blog post, it said that a simulation of Google’s task could be done in 2.5 days on a conventional computer with enough hard drive storage, not 10,000 years.

Last year Amazon announced the launch of the AWS Center for Quantum Computing, which aimed to bring together researchers from Amazon, the California Institute of Technology and other academic research institutions to develop new quantum computing technologies.