Tom
Regardless if the ship is not a Sovereign Ship or it is in international waters someone still owns it, unless it was registered as abandoned which is unlikely. OMR have to prove abandonment not the owners prove it is still theirs, as it was impossible to salvage a ship or cargo delicately at that depth until just a few years ago let alone find such a position of a ship without the use of Computers and hi-tec gadgets which are really relatively young. OMR have technically taken the cargo without permission, shipped it through one country to another then make the claim it’s theirs (finders keepers), so to anyone who thinks its belongs to them, then you have to make a claim against OMR. Well Spain have done. However until they release the name of the ship then no one including Spain or OMR can claim anything. At this time the cargo recovered is in limbo until OMR release the name of the vessel.
Salvage law is a very complicated business, even the famous “Lloyds open form” is not as simple as you would imagine. It fact it’s quite complicated to use.
I must admit though that the owners of sunken ships (in shallow water) usually want to forget about the ship rather than continue to claim ownership, it costs a fortune to remove sunken ships. Just ask any of the P&I Clubs who basically control the business these days.
OMR’s find would unlikely be insured so the onus is with the original ships owners and the owners of the cargo.
We will not go into where the cargo came from originally in terms of The New world that’s just too complicated.
Its clear that OMR”S design is to keep the ships name secret and if they are not sure then that’s probably the correct thing to do rather than have to change the name at a later date should their first conclusion prove wrong. However if they have the providence then they should be talking to the real owners of the wreck and cargo as best as they know who they are and negotiate a settlement favorable to all parties (somebody owns the stuff not OMR they have to get the rights to recover and distribute whatever settlement is made if any).
OMR’s actions have in my opinion shown that they are a very shady operator by their method of recovering this cargo and its removal. They have a partner, the UK government who OMR have been working with for a long time on the Sussex Project (OMR”S flagship project) and also a liaison with the Spanish Government over the same ship. I think they would have come out on top if they had made their find known to both parties, not the exact position but a small recovery of artifacts to prove the nationality of the ship as best as known, spent more time on recovering something more identifiable than the coins, a few cannons would have helped a bit and any other things they may have come across. A softly softly approach would have worked better in the long run, but I see that OMR wanted to move to the NASDAQ Board so they used this publicity to their short term advantage. (Very short sighted I think)
They would have then negotiated their position and would not be in the position now of having to spend tons (and I mean tons) of shareholders cash on the in-suing legal battle that they will have to fight. And even later there will be more claims against them and while you may think having the coins in a bank in the US is a good thing, for OMR it would be better if it were still on the seabed for their case, much safer than a bank or government even the US government.
OMR have a very active PR department who aim at the US market in general, the majority of the rest of the world do not think the same way as the American mindset regarding court cases, so there spin doctors are only really getting the US market the rest of us tend to think the US law system is very strange and is only another place to make money regardless of guilt or innocence. (This is not a personal attack on the US but it’s a clear observation by myself who has been expatriate for over 30 years and lived in many countries including the US).
Imaging that you had decided to move from the US to Bermuda and decided to change all your money into gold and take it on a Yacht for a lovely sail from Miami to Bermuda with no insurance. But on route you hit a very big storm and you lose all power the batteries get swamped and you navigation disappears completely, the yacht is blown for a few days and eventually sinks in deep international water with all your gold on it. You survive but have no idea where the boat sank nor could you afford to recover the gold in the deep water anyway.
But have you abandoned the gold or is it still yours forever

??
When does it stop being your property just because you cannot find it

??
If you drop you wallet on the street in Brazil or anywhere it is still yours however unlikely it would be recovered, if some one did find it and gave you back the wallet and contents would you hand over 90% of what was in it as a reward, not a chance.
However if someone found it and pocketed it, then left the country back to the US then said I have your wallet what are you going to do about it. This what OMR have done, only thing is at this time we are unsure of who owns it, but for sure not OMR they will have to get a reward/award whatever.