This fall people have asked me several times when to buy Theros cards. I have always answered "between December 15 and New Year". That is still my answer, but let us examine if that is really the truth, using data from the last Three fall sets, as well as considering how the non-existence of Daily and bigger events affect this.
When should you have bought Return to Ravnica cards?
One of my favorite MTGO Finance sites, mtggoldfish.com, has a very useful index function.
Let us look at the index for Return to Ravnica here:
http://www.mtggoldfish.com/card/RTR
So the bottom prices of RTR were Dec 14 2002, Jan 5, 2013 and Another dip on Feb 9, 2013.
That does reflect well on our hypothesis, but we also need to consider the differences between Theros and RTR. Theros will be drafted all year, first alone, then with Born of the Gods and finally with both Born of the Gods and Journey into Nyx, whereas Return to Ravnica was not drafted at all during Gatecrash.
Let us look at the fall set of 2011 then.
When should you have bought Innistrad cards?
We are only considering the Standard Life span of the cards here, so the real answer ("right after rotation!") is not relevant to our Theros discussion.
Here is the ISD index:
http://www.mtggoldfish.com/card/ISD
We have the two deepest bottoms at Nov 29, 2011 and Feb 22, 2011 but then ISD drops again (!) and reaches its very lowest Point in May 2012, right around the release of Avacyn Restored.
ISD was also drafted differently. It was drafted with its first small set, DKA, but then it was not drafted at all during Avacyn Restored.
We will need to look at Scars of Mirrodin, which was actually drafted just the way that Theros will be drafted. What did that do the price of rares and mythics from SOM?
When should you have bought Scars of Mirrodin cards?
Once again ignoring the huge effect of rotation, lets have a look at the index:
http://www.mtggoldfish.com/card/SOM
There is again a valley around Christmas. The very lowest points are Jan 17, 2011 and March 3rd, 2011, but then something strange happens. There is a huge dip! On June 16, 2011, SOM prices are as much as 20% lower than in February. There is also very importantly no significant spike in prices during the first two quarters of the year. The spike comes right when M12 is released.
Goldfish has no data for Zendikar. If anyone knows where to find that data, let me know.
What will be the effect of the non-existence of Premier and Daily events?
All events bigger than 8 players are gone from Magic Online when I write this. This has caused prices to drop. This will probably accentuate the drop around Christmas, making picking up cards in December more attractive than what would have otherwise been the case.
Standard PTQ Season
This year, Standard PTQ Season has been moved. It now runs from December 7, 2013 until March 9, 2014. This probably means that Standard prices will go up as soon as PTQs return to Magic Online and that they will drop more sharply during the second quarter without PTQ support.
The conclusion
It is probably premature to buy into Theros in December and if you can wait until May/June, you should do so. My suggestion? Buy playsets that you need (I will do so, especially as I advocate Selling Everything from Theros block as early as in March 2015 with the current PTQ season Schedule unchanged) in December and then buy your speculation stock in May/June.
Instead of spending $100 this month on a google ads campaign or so, allow yourself $100 of loss in MTGO and see the great results that can bring in the long run. Bump all buy prices 5%-10% (depending on how high you buy them) for a week or so, and do announce it! The same goes to sell prices.
