Question 1 of 5
According to research cited on portfolio diversification, roughly how many stocks deliver most of the risk reduction available?
Show answer
The answer is A: About 20
One study found single-stock risk of about 49% fell to about 20% with 20 stocks, against market risk of about 19%. Adding more stocks beyond 20 gave little extra reduction.
Why the other options are wrong
- B
- Most of the reduction comes much earlier.
- C
- Going from 20 to 1,000 stocks reduces risk by less than 1%.
- D
- Risk is still well above market risk with so few.