Stocks to watch on the Australian stock exchange at noon:

BEN - BENDIGO AND ADELAIDE BANK LTD - up six cents at $6.90

Bendigo and Adelaide Bank's new chief executive, Mike Hirst, takes up his role on Friday.

BHP - BHP BILLITON LTD - up 60 cents, or 1.77 per cent, at $34.50

FRS - FERRAUS LTD - up two cents, or 4.2 per cent, at 50 cents

MTH - MITHRIL RESOURCES LTD - down one cent, or 6.7 per cent, at 14 cents

BHP Billiton Nickel West and Mithril Resources have withdrawn from the Silver Swan North nickel and gold joint venture, with full ownership of the project reverting to FerrAus.

NHF - NIB HOLDINGS LTD - up 1.5 cents, or 1.7 per cent, at 90 cents

Private health care fund NIB Holdings says policyholders number grew by more than expected in 2008/09, and that it expect economic conditions be difficult in the new financial year.

PLB - PLAN B GROUP HOLDINGS LTD - untraded at 50 cents

Wealth management firm Plan B Group Holdings has acquired mortgage broker Aspire Finance (WA) Pty Ltd through a combination of debt and equity.

RIO - RIO TINTO LTD - yo 79 cents, or 1.5 per cent, at $52.39

Rio Tinto plc, the UK-listed entity of the dual-listed miner, says it received valid acceptances for almost 97 per cent of the 524 million new shares it offered in the rights issue that closed overnight. Rio's largest shareholder, Chinalco, has taken full part in a $US15.2 billion issue.

WBA - WEBSTER LTD - down three cents, or five per cent, at 57 cents

Walnut and vegetable producer Webster has appointed David West as its chief executive, commencing August 3.

WBC - WESTPAC BANKING CORPORATION - down five cents at $19.63

Westpac has scrapped its retail shareholder benefits package, due to increasing administration costs and very low take-up of the benefits on offer.