This is a dirty little tactic institutions use to manipulate price!
There seems to be a correlation between the price movement of most equities and the 29th and 30th of each month, particularly January, April, July and October. If your charting look for those dates on each month and draw a trend line on the daily close on those dates and see what you find. Institutions favor prices around those dates. Look up Citigroup global markets and 424(b) they sell those to institutional investors and institutions run price to their favor on the named equity on the 424(b).