Whenever a customer's market is changed, or the market's lock status changes, this information is tracked.
(More)
These changes include:
Initial Market and Locked values that were set when the account was first created
When the user updated the Market from one value to another
When the user updated the Locked property on the Market from Locked to Unlock or vice versa
The Market Change History form can be opened from a customer form, from the Status drop down menu.
(Show Picture)

The fields are described here:
Change Date | Date and time that the change occurred |
Change Reason | Reason that the market was changed. (Options are from the Market Change Reasons table in Admin Console.) |
Market From | Name of the previously associated market (if any) |
Market To | Name of the new market |
Locked From | Whether the market was Locked or Unlocked before the change |
Locked To | Whether the market was Locked or Unlocked after the change |
User | Name of the user who made the change |
Description | Any additional details that the user may have entered when filling in the Market Change Detail. (It is displayed in lower pane when highlighting a row in the upper pane.) |