In trading on Wednesday, shares of the iShares U.S. Basic Materials ETF ( IYM) crossed below their 200 day moving average of $83.81, changing hands as low as $83.49 per share. iShares U.S. Basic Materials shares are currently trading off about 0.7% on the day. The chart below shows the one year performance of IYM shares, versus its 200 day moving average:Looking at the chart above, IYM's low point in its 52 week range is $76.12 per share, with $89.46 as the 52 week high point — that compares with a last trade of $83.48.