Some dealerships use last 6 of the VIN but that has some limitations and does not tell you too much. Probably the most common is:
New 9P001
9 = 2009 model
P = Pontiac
001 = first 2009 stocked in
Trade in - 9P001A
The sold stock number with a letter added A,B,C etc. until there is no trade in.
Purchased used cars: U0001 P0001, C0001
U = used P = Program C = Certified
There are variations on this and if but it should accomodate the 2010 models (0P001) with no problem.
Note that since this is an alpha/numeric field your DMS most likely sort it "alphabetically". This will be consistent if you always use the same number of digits 9P001 not 9P1 or 9P01.
Obviously if you have stock in over 999 2009 Pontiacs this would be an additonal challenge.
Whatever the numbering scheme chosen it is imperative that a stock number get assigned to a unit immediately and a stock number log is helpful. Have witnessed some royal messes when 2 units get the same stock number or a unit gets a stock number late.
Have a great weekend - go sell something today hopefully at a profit!
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Have a tremendous day
Bob Britting
[This message has been edited by JustBob (edited 03-20-2009).]