* Dalian iron ore down as much as 5%
* Spot prices for benchmark 62% Fe at $96.5 a tonne
* Demand can be sustained but hard to grow - trader (Adds details, quotes, updates closing prices)
BEIJING, Sept 19 (Reuters) - China's Dalian iron ore futures stumbled on Thursday, extending losses to a fourth session, on concerns about future demand.
The most-traded iron ore futures contract, on the Dalian Commodity Exchange, for January 2020 delivery, fell as much as 5.2% to 634 yuan a tonne, the biggest intraday loss since Aug. 21. It closed down 4.6% at 638 yuan ($89.82) per tonne.
Prices for spot cargoes of benchmark iron ore with 62% iron content for delivery to China, fell for a second straight day on Wednesday to $96.5 a tonne.
Investors are cautious as prospects of China's economy remain uncertain, a Shanghai-based trader said. Demand can be maintained at the current level but is unlikely to grow further, said the trader, adding that supply of iron ore is relatively sufficient now.
The most-active construction steel rebar contract on the Shanghai Futures Exchange, for January delivery, fell 3.3% to 3,397 yuan per tonne.
Hot-rolled coil steel, used in cars and home appliances, on the Shanghai Futures Exchange, fell 2.8% to 3,428 yuan a tonne, also fell for a fourth straight day.
A huge outflow of funds from the equities market is affecting sentiment in the ferrous complex, said Tivlon Technologies, a steel and iron ore data analytics firm.
"We are seeing funds outflows accelerating this week and it looks like further soften(ing is) to come," said the Singapore-based company.
* Other steelmaking ingredients also fell, with Dalian coking coal down 1.5% at 1,319 yuan a tonne, while coke dipped 1.1% to 1,963 yuan.
* China's local governments issued a net 2.0057 trillion yuan in special bonds in the first eight months of the year, the finance ministry said on Wednesday, as Beijing looks to spur infrastructure investment and stabilise the cooling economy.
* The U.S. Federal Reserve cut its target interest rate by 25 basis points to a range of 1.75-2.0% on Wednesday to help sustain a record-long economic expansion but signalled a higher bar to further reductions.
* China's yuan fell to its weakest level in a week after the U.S. Federal Reserve refrained from promising more interest rate cuts beyond its freshly-made one, prompting markets to bet on a stronger dollar.
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($1 = 7.0931 Chinese yuan) ($1 = 7.1031 Chinese yuan renminbi) (Reporting by Min Zhang and Tom Daly; Editing by Aditya Soni and Emelia Sithole-Matarise)