In my experience end of the year (approx mid December) is typical to have a significant dump of coins due to traders locking in profits before the end of the year, people going on holiday and needing money, etc.
Yes this is more likely happen during December, I`m a holder, but somewhat I failed to hold some tokens and it keeps dragging me down until now why I didn't sell in December. It's a big mistake for me, not to ask somebody, well anyway being a novice in trading and holding always experience something like this.
It happens but not in all situation. There cases that some holder became rich at the end of the year and there are also holder remains the same. It depends on the currency of the token they have. The higher the currency the higher the possibilities that the income will be higher.