In the cases I've been involved in, it has largely been oil companies or their subcontractors footing the bill, occasionally scientists or, uh, treasure hunters

In the cases I've been involved in, it has largely been oil companies or their subcontractors footing the bill, occasionally scientists or, uh, treasure hunters. (I work for a company making this exact type of recovery gear, so every now and then I have to do some field work)