John, I think you're referring to the 200 day moving average (200 MA). If you look to the legend on the left you can see the 200 day MA is in red and the 50 day MA is blue.
On top of what Rick said, when the 200 dma crosses the 50 dma, this is called a "Golden Cross". It is a VERY bullish signal that will send day traders flooding into KATX for a time. The bullish sentiment generally continues until the 2 DMA lines approach one another on the other side and return to a "normal" trading pattern.
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