I just found an awesome web site that has a history of Ebay sales prices. http://www.pixel-peeper.com/cameras/?camera=19&tab=2
I ran the numbers through a basic forecasting model, using the following adjustments.
- correct for seasonality
- correct for a simple linear trend
- take the de-seasonalized, de-trended pattern of 5D sales after the 5DII launch, apply that pattern to the 5DII... then reapply seasonality and downward trend.
I did not correct for
- Economic chaos of 2008/2009
- shipping problems
The II was announced Sep 17, 2008 and began shipping 75 days later
The III was announced March 2, 2012 and I just put May 16 (75 days) as the ship date to simplify the math.
Here's what I learned:
The best months to buy a body: Jan/Feb/Mar
The best months to sell a body: May/July
In general, prices drop about 1.4% per month.
Right after the 5DII announcement there appeared to be a little sell panic and the 5Dc price dropped about $500
When the 5DII actually started shipping, there appeared to be a little buy panic (people thinking they could snap up a good deal on a 5Dc) and the price shot up, rising above the historical average.
Prices dropped again 3/4/5 months after the II began shipping because supply was high and demand calmed down.
But then the price rebounded - and a year after announcement, the price finally stabilized and began a predictable downward march.
Sell Recommendation: Sell your II May/June/July of this yearHere's what popped out of the model:Disclaimer: Prediction is very difficult and unreliable, especially when it's about the future
Version 1.1 (I had my curves shifted a month)