### Instruction: Extract the stages for portfolio optimization from https://en.wikipedia.org/wiki/Portfolio_optimization
### Input: Portfolio optimization often takes place in two stages: optimizing weights of asset classes to hold, and optimizing weights of assets within the same asset class. An example of the former would be choosing the proportions placed in equities versus bonds, while an example of the latter would be choosing the proportions of the stock sub-portfolio placed in stocks X, Y, and Z
### Response: - Stage 1 is optimizing weights of asset classes to hold, choose the allocation of equities and bonds
- Stage 2 is optimizing weights of assets within the same asset class, choose the proportions of each stock stickers in the stock portfolio