Dornier plc is a large civil engineering business that is listed on the Stock Exchange. On 1 May it received a confidential letter stating that it had won a large building contract from an overseas government. The new contract is expected to increase the profits of the business by a substantial amount over the next five years. The news of the contract was announced publicly on 4 May.

How would the shares of the business react to the formal announcement on 4 May assuming (a) a semi-strong, and (b) a strong form of market efficiency?