The Rio Tinto Ltd (ASX: RIO) share price fell 3.7% to an intraday low of $113.12 despite encouraging news for iron ore demand out of China today.

The main factor dragging Rio Tinto shares down is that they began trading ex-dividend today.

Share prices usually fall on ex-dividend days simply because the stocks are less appealing for investment without the upcoming dividend attached.

However, it's worth noting that the ex-dividend day can present a useful dollar-cost averaging opportunity for long-term investors because they can pick up more stock at a lower price.

The Rio Tinto share price has recovered somewhat from its earlier fall.

Rio Tinto shares are currently trading at $115.26, down 1.19%.

The BHP Group Ltd (ASX: BHP) share price is also lower today after also going ex-dividend.

BHP shares are trading 0.8% lower at $39.23.

Meantime, Fortescue Ltd (ASX: FMG) shares are up 1.07% to $16.10.

With no company news out of Fortescue today, the price spike is likely due to news out of China.

China sets 2025 economic growth target

China is currently holding its annual National People's Congress (NPC) event.

This is where annual economic growth targets and various new policies are revealed.

Indeed, China's Premier Li Qiang has just announced the 2025 economic growth target.

The target is 5%, same as last year, along with a fiscal deficit target of 9.9% of China's GDP.

As my colleague Bernd reports, that's the highest deficit level in more than three decades.

It's high because the economic growth target will likely require significantly more stimulus.

Additional stimulus would come on top of other measures announced last year to shore up the economy and support the flagging residential property sector.

Those announcements included extra capital for Chinese banks and continued debt relief for local councils.

At the NPC, China also announced an increase in special bond sales to boost infrastructure spending.

Higher infrastructure investment will likely mean more demand for iron ore to make steel.

This is all encouraging news for ASX 200 iron ore stocks like Rio Tinto and its peers.

Rio Tinto share price falls as dividend entitlement disappears

Rio Tinto declared a fully franked final dividend of 225 US cents per share for FY24.

Rio Tinto shareholders will receive their dividend payment on 17 April.

Last month, the miner reported a 1% fall in sales revenue to US$53.7 billion and a 15% lift in net profit after tax (NPAT) to US$11.55 billion over the 12 months to 31 December.

Despite this, the Rio Tinto board decided to lower the full-year dividend by 8% to 402 US cents.