Stocks to watch on the Australian stock exchange:

AGO – ATLAS IRON – up 0.25 cents, or 5.95 per cent, at 4.45 cents

FMG – FORTESCUE METALS GROUP – down nine cents, or 1.9 per cent, at $4.55

Australia mining magnate Gina Rinehart has stepped into the takeover battle for Atlas Iron and, like Fortescue Resources, now controls a blocking stake in the junior miner.

APA – APA GROUP – up $1.73, or 20.9 per cent, at $10.00

Shares in energy infrastructure giant APA Group have soared following a $13 billion takeover proposal from a Chinese consortium led by CK Infrastructure Holdings.

IOF – INVESTA OFFICE FUND – up one cent, or 0.2 per cent, at $5.14

Investa Listed Funds Management has entered a binding agreement for US private equity giant Blackstone to acquire the ASX-listed Investa office Fund in a $3.14 billion deal.