Short Term Trading Member Forum

[mr_cash4]

re. zero-sum, I need you guys to answer the following (simple) question:

In January I buy 5,000 shares of MSFT at $20 ($100,000 total investment). In december I sell those 5,000 shares of MSFT at $24.00, receiving $ 120,000, i.e. my principal plus $20,000 in profits.

where did the $20,000 come from??????????????????