(Reuters) - Germany's Aurubis said it had appointed Toralf Haag as its new chief executive, effective Sept. 1.

Tim Kurth, a managing director of the Bulgarian branch, will be appointed Chief Operations Officer for custom smelting, the company added in a statement on Thursday.

In January, the copper producer said it had agreed to terminate the contracts of its chief executive and chief financial officers in a top-level reshuffle over their handling of an alleged theft and fraud.

Aurubis shares were up 4.67% as of 1444 GMT but had begun rising hours before the announcement, trading up 7.2% as of 1226 GMT.

A local analyst pointed to a report by German business publication Manager Magazin to explain the earlier move.

The report said major shareholder Salzgitter had in the past looked into the possibility of acquiring more shares in Aurubis and had mandated two investment banks to "calculate the project".

Salzgitter reaffirmed it had "at present" no interest in taking over Aurubis, the magazine reported.

(Reporting by Louis van Boxel-Woolf and Paolo Laudani, editing by Andrey Sychev and Thomas Seythal)