* Global markets fall as China starts tightening policy
* Commodities hit hard on fears Chinese demand will slow
* Commodity currencies such as Aussie dollar also retreat
HONG KONG, Jan 13 (Reuters) - Stock markets and commodities fell in Asia on Wednesday after Beijing's surprise decision to raise banks' reserve requirements sparked concerns that China's rapid economic rebound would slow, curbing demand for natural resources and other imported goods from around the region.
High-yielding "commodity" currencies such as the Australian dollar <AUD=> also weakened after the move by the People's Bank of China late on Tuesday, which appeared to be prompted by concerns that inflation could flare up if the economy overheated. [
]But the yen strengthened on short-covering as investors unwound trades linked to a broad range of higher-yielding assets, while U.S. Treasuries and Japanese government bonds also gained in response to weaker stocks.
A disappointing start to the U.S. earnings season also weighed on investor sentiment with a profit warning from Chevron Corp <CVX.N> following on th heels of weaker-than-expected results from aluminum maker Alcoa Inc <AA.N>. The S&P 500 ended 0.9 percent lower. [
]Fears that China is getting ready to use more forceful measures to cool the economy, including interest rate hikes, also pulled down U.S. and European stocks on worries about a potential slowdown in Chinese demand, with exporters facing the brunt of the selling.
While China is stepping in to moderate rapid economic growth, many Western countries are still trying to stimulate demand. The MSCI index of Asia Pacific stocks traded outside Japan <.MIAPJ0000PUS> was down 0.46 percent, pulling away from the 17-month high it struck on Tuesday. The index of materials stocks <.MIAPJMT00PUS> was down 1.1 percent.
The Thomson Reuters index of regional shares <.TRXFLDAXPU> was down 0.17 percent.
Shanghai shares <
> opened 2.1 percent lower.Commodity-linked currencies such as the Australian and New Zealand dollar <NZD=> were both on the defensive following the moves by China -- a major importer of commodities.
Shanghai aluminium fell by its 5 percent daily limit and zinc also came close to its downside threshold.
Benchmark third-month Shanghai aluminium <SAFc3> fell 900 yuan to 17,085 in early trade, while zinc <SZNc3> dipped to 20,110 yuan, just 25 yuan short of its downside limit.
The PBOC said it will increase commercial lenders' reserve requirement ratios (RRR) by 50 basis points as of Jan 18, making China one of the largest economies to start rolling back the emergency policies used to combat the crisis fallout.
The bank reserve increase also followed two other tightening steps taken by the PBOC bank on Tuesday.
The central bank raised the yield on its regular sale of one-year bills by about 8 basis points, the first increase in 20 auctions and higher than forecasts for a rise of 4 basis points.
It also drained a record 200 billion yuan via 28-day bond repurchase agreements, ensuring it will draw net funds from the market this week. [
] (Reporting by Umesh Desai)