Looking at the universe of stocks we cover at Dividend Channel, on 5/29/13, Arch Coal, Inc. ( ACI) will trade ex-dividend, for its quarterly dividend of $0.03, payable on 6/14/13. As a percentage of ACI's recent stock price of $5.37, this dividend works out to approximately 0.56%, so look for shares of Arch Coal, Inc. to trade 0.56% lower — all else being equal — when ACI shares open for trading on 5/29/13.Below is a dividend history chart for ACI, showing historical dividends prior to the most recent $0.03 declared by Arch Coal, Inc.: In general, dividends are not always predictable; but looking at the history above can help in judging whether the most recent dividend from ACI is likely to continue, and whether the current estimated yield of 2.24% on annualized basis is a reasonable expectation of annual yield going forward. The chart below shows the one year performance of ACI shares, versus its 200 day moving average: Looking at the chart above, ACI's low point in its 52 week range is $4.47 per share, with $8.86 as the 52 week high point — that compares with a last trade of $5.36. According to the ETF Finder at ETF Channel, ACI makes up 3.69% of the SPDR S&P Metals and Mining ETF ( XME) which is trading higher by about 0.7% on the day Tuesday. In Tuesday trading, Arch Coal, Inc. shares are currently up about 1.1% on the day.