If the investors aren't shutting down Theranos, then there is a possibility their due diligence on Holmes' patents held out hope of patent trolling someone with deep pockets in the future, or some other similar hope pinned upon those patents. My limited layman's understanding of their microfluidics-based claims is they violated currently-known assaying principles. Hope someone with deeper knowledge about this can pipe in, I've only seen some rants from claimed clinicians when they first announced way back, with terms that went way over my head, and they summed up the rant's TL;DR as, if she really figured it out, she'd be publishing and collecting a Nobel or two, as she would've upended a century of what we believe is statistically possible.
However, if instead of using their "nanotainer", a fancy name for a very small blood sample container, some future microfluidics implementation used in vivo implanted chips, and can build up a sampling profile over time say, and some of her patents stand smack in the road of that deployment, then they could recoup some of their money.
There were a number of patents assigned this year. Surprisingly many, for a company in seemingly so much trouble [1]; this display makes it easier to see the assignment dates [2]. Perhaps this is staying the hand of the investors for now, and they're performing some independent due diligence.
However, if instead of using their "nanotainer", a fancy name for a very small blood sample container, some future microfluidics implementation used in vivo implanted chips, and can build up a sampling profile over time say, and some of her patents stand smack in the road of that deployment, then they could recoup some of their money.