Person A holds 1 stock, valued at 100. Person A sells 1 stock to person B. Now Person A holds 100 in cash, and 0 in assets. Person B now holds 0 in cash, and 1

Person A holds 1 stock, valued at 100. Person A sells 1 stock to person B. Now Person A holds 100 in cash, and 0 in assets. Person B now holds 0 in cash, and 100 in assets. Fast forward 5 years. The stock price has crashed to 1 dollar. Person A still holds 100 in cash and 0 in assets. Person B holds 0 in cash, and 1 in assets. There was no transfer of 99 dollars back from Person B to Person A. Person A's holdings were invariant because they don't own the stock anymore. The losses brunt by Person B were not transferred to anybody else. Money doesn't travel back in time.