OK, so we can test to see if there is a statistical correlation but even if we did find that there is a definite similarity in the patterns of fluctuation between sunspot activity and global finances we would still need to locate the connecting agent.
For example, we know (or at least we are told that someone thinks they know) that the Polar Auroras fluctuate in accordance with sunspot activity and we also (think we) know the causal connection - the solar wind dropping charged particles into the Earths magnetic field which is concentrated at the poles. The chain of processes starting from the ejection of plasma from the sun to it's interaction in the upper atmosphere are well understood - the processes involved can be predictably reproduced in laboratory conditions.
There is (as far as I know anyway) no known mechanism to explain how sunspot activity might affect financial activity - although as a starting hypothesis we could test to see if increased sunspots trigger increased aurora's which perhaps increases the global atmospheric percentages of free negative ions, known to affect moods in humans. More sunspots, means more negative ions making people feel happier and more secure and therefore more inclined to spend money.... you get the idea.
Identifying a statistical correlation does not, in and of itself, prove there is a causal connection - which I why I said we can't test this theory.
This what I find interesting - does this mean there is a correlation between sunspot activity and the likelyhood of major wars?
Also does this prove our sunspot hypothesis - two examples are not really able to indicate a statistical correlation. Additionally there are other factors that are known (or at least thought) to be working on the longterm economic trends. I recall reading some time back about the Century Effect whereby over the last few centuries there has been a marked increase in financial activity and general economic growth in the first few years of a new Century. Science historians have also noted that it is common for new theories and scientific concepts to emerge around the turn of a century and that this will tend to drive scientific thought for the rest of that 100 years.
Certainly any boom period is eventually followed by a responsive bust period where the economy, having overstepped itself, falls into a recession. And any student of history can tell you that warfare stimulates economies.... perhaps it was this Century Effect, linked to natural human optimism at the start of a new Century, that triggered the boom that lead to the bust that led to the threat of war in Europe leading to "A year of general economic decline caused by the withdrawal of European capital from world markets". Occams Razor, favouring the simplest theory as the 'right' one, would suggest sunspots had nothing at all to do with the economics of 1913.
This is probably not surprising - I suspect that if there were a distinct statistical correlation between sunspots and world economics someone else would have noticed it by now
Mmmmh! Money!

Actually I'm less interested in the theory and it's validity than I am in the way people perceive these patterns - the human brain works like a pattern recognition device and does so very well, so well that we see patterns where none exist (shapes in the clouds, non-existent faces at the window etc.
My 'real' theory is that this pattern recognition ability of the human awareness is what is responsible for much in human experience that is classed as Magic, as Prophecy, as ESP and as Religion, particularly when it comes to the religion of miracles and pictures of the Virgin Mary toasted into someones breakfast!
So the reason I've called this thread As Above So Below is because I believe it's more like what's inside (our heads) is what is outside!
There is no reality only perception.
Any takers?