Apple (AAPL) is probably the most widely followed individual stock in the US, so it's important anytime it experiences a bullish or bearish technical signal. Unfortunately, today the stock's technicals took a major turn for the worse since it closed below its 200-day moving average. When a stock is above its 200-day, it is thought to be in a long-term uptrend, and it is thought to be in a long-term downtrend when it is below its 200-day.
In Apple's case, it has spent the better part of the last 10 years above its 200-day moving average, and today marked the end of a 551-day run of consecutive closes above its 200-day. The last time Apple closed below its 200-day was on April 8th, 2009. The 551-day streak of closes above the 200-day was the second longest such streak for Apple in its history. The longest streak of closes above its 200-day came in the mid-2000s when it did so for 769 days.