BY JOANN S. LUBLIN

Oil-drilling contractor Nabors Industries Ltd., already under attack for its executive-pay practices, faces new pressure from public pension-fund systems in five states.

The shareholders want to give investors more power to oust Nabors directors. Public pension funds in California, Connecticut, Illinois, New York and North Carolina said Tuesday that they have proposed giving Nabors shareholders the right to list board candidates on official company ballots, which currently list only management's choices.

The funds collectively own about 1.7 million of Nabors's 288 million shares. The company's stock has lost about a quarter of its value this year. Nabors shares fell 25 ...