Arcam has a "natural monopoly" on powder EBM with patents that help Arcam recoup their research costs so there's no reason to act on Arcam. There's also the competing technology on wire fed EBM, GE is not buying that, so I think there may be an argument in GE's favor EBM wise. It's that GE could own important laser and electron beam additive manufacturing firms that may attract the attention of some government agency.
GE is interested in innovation but I believe they're buying because they have their eye on the bottom line. Here's an interesting little article from 2014 about GE and 3d printing.
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