Are US stocks generally cheaper in Dec since people who want to avoid capital tax gain would try to sell off their stocks before the end of year?

Most fund managers sell thei positions at the end of year holiday seasion to avoid unexpected natural disaster e.g . 2004 Indian Ocean earthquake and tsunami

https://en.wikipedia.org/wiki/2004_Indian_Ocean...

Forgot was it Peter Lynch or John Templeton who said this. back in their days, fund managers sell positions to take a break at the end of year holiday season.