Even Kim Seong-geun earned massive lecture fees when he was the Wonders manager

[Society] Star professors earning hundreds of millions in lecture fees alone, what should be done?n.news.naver.com[Weekly Dong-A] National and public university professors are restricted to 300,000 KRW due to the 'Kim Young-ran Act'... Debates intensify ahead of the enforcement decree confirmation. A scene from a lecture by Michael Sandel, a professor at Harvard University, held at Kyung Hee University in 2010. [Dong-A Ilbo] Every Wednesday morning, the Samsung Group holds special lectures for approximately 50 executives. Those invited as speakers to this event, known as the 'Samsung Executive Lecture Series,' are individuals with profound insight...
In fact, professional baseball manager Kim Seong-geun of the Hanwha Eagles once stated in a media interview last year, "I paid nearly 300 million KRW in taxes alone for lecture fees last year." Under current tax laws, a 4.4% tax rate is applied to lecture fees. Based on this, a simple calculation suggests that Manager Kim's annual lecture income would be estimated at over 6 billion KRW.
* Since that was the tax amount as of 2014... if you were to invite him as a speaker now, you should expect it to start from at least 5 million KRW