Stock investment guides and celebrity-recommended books were popular. According to the Yes24 comprehensive bestseller list for the fourth week of January, <The Essentials of US Stock Investment> by Choi Cheol ranked first. The author is the operator of a stock investment YouTube channel. Second place went to <The Words of Buddha Translated by the First Translation> by Japanese monk Koike Ryunosuke. This book reinterprets the words of Buddha in modern language, and after Jang Won-young, a member of girl group I.B., recommended it on a broadcast on the 15th, sales increased 51-fold over the previous week in the seven days.