it is a safe bet what is meant: The upper 10,000 richest.
Since (unfortunately) the most intelligent or discerning, or even noble people do not always have money too, I am sorry to say that I meant it moneywise.
If you have seen the film "High society" with Grace Kelly, Frank Sinatra, Bing Crosby etc., based on a theater play (the Philadelphia story if I recall well), which in other languages was called the upper 10,000, you will understand the meaning.
The persons in this film were "only" rich and wealthy. But they were regarded as the upper 10,000.
I hope that you are satisfied with my answer, it is the only one I can give.