Under takeover laws in Luxembourg, where Arcelor is based, shareholders who havent tendered their stock to Mittal will receive a minimum of 40.40 euros in cash.
Investors may also be able to receive Mittals offer in stock and cash, and make a profit on a potential increase in the new companys value,according to Renaud Berenguier, head of hedge-fund equity sales at Aurel Leven SA in Paris.
You know you are going to get 40.40; that's your floor, Berenguier said in an interview.
There's a certain level where the Mittal stock price will be above 40.40 a share, he added.
Arcelor's shares rose as much as 2.92 euros, or 7.4%, to a record 42.50 euros, and traded at 42.10 euros at 12:26 pm in Paris. The stock has almost doubled this year.