1. The problem asks for the number of proper subsets of the set $L = \{\text{Bill Gates}, \text{Warren Buffett}, \text{Larry Ellison}, \text{Jeff Bezos}, \text{Charles Koch}, \text{David Koch}, \text{Mark Zuckerberg}, \text{Michael Bloomberg}\}$ which contains 8 elements. 2. Recall that the total number of subsets of a set with $n$ elements is given by the formula: $$2^n$$ This includes the empty set and the set itself. 3. Proper subsets are all subsets except the set itself. So, the number of proper subsets is: $$2^n - 1$$ 4. Substitute $n=8$: $$2^8 - 1 = 256 - 1 = 255$$ 5. Therefore, the set $L$ contains $255$ proper subsets. Final answer: $255$ proper subsets.