Short answer

When you apply a 200-month moving average:

You need 200 data points to calculate the average

This translates to 16.6 years of monthly data

Many stocks don’t have sufficient historical data spanning this period

Charts will not display the moving average if adequate data points are unavailable

What you can do

Use shorter time periods for moving averages on stocks with limited historical data

Check if the stock has been listed for at least 16.6 years before applying long-term moving averages

Consider using shorter moving averages like 50 or 100 months for better visibility

You can learn more about moving averages by visiting Technical Analysis module on Arrow learning resources.