Utility Exelon Corporation has dropped a $7.53bn offer for NRG Energy after shareholders rejected its board nominees, which has brought to an end a nine-month takeover battle.

Stockholders voted in Princeton, US, where NRG is based, to elect the company’s slate of four directors over independent candidates nominated by Exelon.

Investors also voted down a proposed expansion of the board to make room for five other Exelon nominees, according to results announced at NRG’s annual meeting.

NRG said that about 75% of shareholder votes were cast in favour of its director nominees.

Exelon, which is the largest operator of nuclear plants in the US, took its offer directly to shareholders after NRG’s board rejected its original bid in October.