So Arcelor have made known a clause in a contract with Nippon that allows the Japanese steel company to withdraw the right to use patent technologies if the ownership of the company changes substantially.
I assume that they hope that this will make them less attractive as a potential take-over target. In fact Nippon is known to have some agreements with Mittal also, and whether or not they would invoke this clause is debatable.
I hold no strong opinion at this point in the desirability of the largest European steel manufacturer coming under the control of Mittal. I am however finding some of the tactics emerging from Arcelor to be tiresome. Only last week there was talk of acquiring US Steel, not as a strategic expansion, but to increase indebtedness and make them a less desirable acquisition.
It is surely for the shareholders (i.e. owners!) to ultimately decide whether or not this bid should succeed. No doubt there are going to be many more twists to this story yet.