* Chinese investors take profit ahead of week-long holiday * ShFE to be closed from Sept 29 to Oct 7 * Chinese companies cut stocks ahead of Q3 results * Coming up: IMF chief Lagarde's speech; 1630 GMT (Updates prices; adds quotes, details) By Carrie Ho SHANGHAI, Sept 24 (Reuters) - Copper eased on Monday but remained near 4-1/2 month highs, pressured by a strengthening U.S. dollar, while profit-taking by Chinese investors ahead of a week-long national holiday sent Shanghai prices lower over one percent. Prices are also weighed down by weak demand from top consumer China, where manufacturers are still waiting to see orders from Beijing's infrastructure expansion schemes. Three-month copper on the London Metal Exchange was down 0.7 percent to $8,222 per tonne by 0729 GMT, after inching up 0.1 percent in the previous session. The most active January copper contract on the Shanghai Futures Exchange fell 1.1 percent to 59,070 yuan ($9,400) per tonne, after gaining 0.7 percent on Friday. "Chinese investors are in profit-taking mode before the national holiday. No one wants to wait till the last day of trading because the margins on that day will be so high," said a Shanghai-based trader with an international firm. The Shanghai Futures Exchange (ShFE) will be closed from Sept. 29 to Oct. 7. for the mid-Autumn and Chinese National Day holidays and it will temporarily hike trading margins for all its futures contracts from Sept. 28 to control price volatility. Margins for ShFE copper, lead and zinc will be raised by 4 percentage points to 12 percent while those for aluminium will be raised by 5 percentage points to 11 percent. "We are approaching the end of September, after which companies will have to file their third-quarter financial results so they are more inclined to clear inventories and close off futures positions," said a second Shanghai-based physical copper trader. A strengthening U.S. dollar, due to increased risk aversion, also weighed on metals and other commodities priced in the greenback because it made them less attractive to buyers holding other currencies. The dollar index measured against a basket of key currencies rose 0.1 percent, with the euro testing last week's low against the dollar on Monday. In physical markets, copper buying by China's downstream industries remains soft despite a modest pick-up in power cable demand due to more tenders offered by China's giant power provider and top cable buyer, the State Grid Corp, over the summer. "In previous years, there used to be a bout of restocking by copper consumers ahead of the National Day holiday since some smelters continue to operate throughout this period," said Shanghai Metals Market research Angela Wang. "We haven't seen that this year, which underlines how weak downstream copper demand is. This has put a slight dent on the optimism over recent stimulus policies." The spread of spot copper prices over the ShFE prompt October price has narrowed to a discount of 50 yuan from a discount of 300 yuan two weeks ago. But market players said this did not indicate a significant pick-up in consumer demand. "It mostly shows that the ShFE Oct futures have fallen faster than spot prices today," Wang added. China's implied consumption of refined copper rose 9.5 percent in August from the previous month, not because of stronger consumer demand but due to fewer exports and increased domestic production, according to Reuters calculations based on official data released on Friday. Base metals prices at 0729 GMT Metal Last Change Pct Move YTD pct chg LME Cu 8222.00 -59.50 -0.72 8.18 SHFE CU FUT JAN3 59070 -670 -1.12 6.18 LME Alum 2096.75 -19.25 -0.91 3.80 SHFE AL FUT DEC2 15665 -75 -0.48 -1.10 HG COPPER DEC2 374.70 -4.20 -1.11 9.05 LME Zinc 2097.00 -18.50 -0.87 13.66 SHFE ZN FUT JAN3 15540 -190 -1.21 5.04 LME Nickel 17945.00 -230.00 -1.27 -4.09 LME Lead 2265.00 -23.00 -1.01 11.30 SHFE PB FUT 15990 -165 -1.02 4.58 LME Tin 20500.00 -250.00 -1.20 6.77 LME/Shanghai arb 1592 Shanghai and COMEX contracts show most active months ^ LME 3-m copper in yuan, including 17 pct VAT, minus SHFE third month

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