Stocks to watch on the Australian stock exchange on Friday, July 17:

PRY – PRIMARY HEALTH CARE – down 42 cents, or 8.1 per cent, at $4.77

Shares in medical centres and pathology provider Primary Health Care have fallen after the company’s earnings forecast downgrade.

RIO – RIO TINTO – up 19 cents, or 0.4 per cent, at $53.31

Rio Tinto has lowered its full year iron ore guidance slightly after bad weather hit its Pilbara operations.

STO – SANTOS – down 11 cents, or 1.4 per cent, at $7.72

The energy producer releases its second quarter production report on Friday.

WHC – WHITEHAVEN COAL – down eight cents, or 6.4 per cent, at $1.165

Whitehaven Coal’s sales are on the rise but it expects prices to continue to fall.

WPL – WOODSIDE PETROLEUM – down 39 cents, or 1.1 per cent, at $34.57

Plunging oil and gas prices have almost halved giant Woodside’s revenue.