AAPL lost as much as 15% in 12 days. What upset the Apple cart? Here are three reasons. Earnings One could say, it all started with the most recent earnings report on July 21. Although earnings were strong, forward guidance was weak. My July 10 columnanticipated post-earnings weakness when it stated: “AAPL tends to pop the day after earnings, but that's not guaranteed. The last all-time high occurred the day after earnings, and it's been down ever since. According to UBS, half of AAPL's revenue growth comes from China. According to FactSet, China accounts for 16.2% of AAPL's total revenue. Chinese stocks are down 30% since June 5. This could make its way into earnings ... and spook investors. AAPL seasonality also suggests being careful in July and early August." Seasonality AAPL seasonality has a rough path from mid July to early August. Click here forAAPL seasonality chart. Open chart gaps My above-mentioned Apple column also brought out that: "In terms of AAPL's 'summer to-do-list', there are open chart gaps at 114.36 and 99.96, which may want to get filled." As the chart below shows, the gap at 114.36 (dashed pink line) was filled on Aug. 4. There is another open gap at 99.96. Broken support On Aug. 3, Apple broke below support at 120. Prior support at 120 is now resistance (red circles on daily chart). On Aug. 3, Apple also fell below a much more significant support level. As the weekly log scale chart shows, the bold green trendline support that goes back all the way to 2009, and failed for the first time last week. This trendline, previously support, is now resistance (currently also around 120). Based on support and resistance levels, the outlook is pretty straight forward: The path of least resistance is down, as long as AAPL stays below resistance (around 120 and rising slowly). A possible downside target is support and the open chart gap around 100. It will be interesting to see how AAPL's performance will affect the Nasdaq and S&P 500. AAPL is by far the biggest component of the Nasdaq and S&P. If AAPL gets a cold, will the Nasdaq and S&P catch the flu? More from MarketWatch