Fortescue Metals Group Ltd (ASX: FMG) shares kicked off today well into the green.
Shares in the S&P/ASX 200 Index (ASX: XJO) mining stock were up 1.8% in morning trade on Tuesday, before giving back those gains, and more.
At time of writing, Fortescue shares are swapping hands for $22.15 apiece, down 0.6%.
But it's not just Fortescue that's come under intraday selling pressure.
The BHP Group Ltd (ASX: BHP) share price was up 0.8% in early trade and is now down 1.4%. And shares in rival ASX 200 mining stock Rio Tinto Ltd (ASX: RIO) were up 0.9% before sliding to the current 0.7% loss.
Taking a broader view, the S&P/ASX 300 Metals & Mining Index (ASX: XMM) has dropped to a loss of 1.4%, while the ASX 200 remains up 0.2% for the day.
So, what's going on?
Fortescue shares waver on China data
It looks like the intraday headwinds battering the big ASX mining stocks are blowing out of China.
China, the world's number two economy, also counts as the biggest export market for Australia's iron ore.
This morning, investors started the day on news that the iron ore price continued to defy forecasts of a retrace, gaining another 1.8% overnight to trade for US$121.80 per tonne.
But investors may now be bidding down Fortescue shares amid concerns ongoing sluggishness in the Chinese economy could crimp the appetite for the critical steel-making metal from China's factories.
Fortescue shares – as with rivals BHP and Rio Tinto – derive the majority of their revenue from iron ore.
And the latest manufacturing purchasing managers index (PMI) data showed a decline to 49.5 in October, down from 50.2 in September. Any figure below 50 indicates a contraction in Chinese factory activity.
This came in below consensus expectations, with a Bloomberg economist survey having forecast the data would hold steady at 50.2 for the month.
China's non-manufacturing index, a gauge of activity in the nation's construction and services sectors, also came in below consensus expectations of 52. Instead, it fell from 51.7 in September to 50.6 in October.
This may see more stimulus measures rolled out by the Chinese government to spur the floundering economy. But today, Fortescue shares and its big ASX 200 iron ore rivals are feeling the pressure.
