Until 1970 the stamp market in the United States was mostly determined by the domestic market alone. Virtually all stamps, both US and Foreign, that were sold in this country were sold to domestic buyers. International travel was unusual and expensive, there was no Internet, and American philatelic auctioneers didn’t send many catalogs overseas. 1970 was a watershed year as it marked the period that the economic balance began to shift between Europe and the United States. Until 1970, Europe was still economically weak and recovering from the devastation of WW II. After 1970, the dollar was devalued several times against the mark and other European currencies, which pushed up prices of these stamps in dollar terms. And the rapidly expanding European economies gave consumers there more money to pursue their hobbies also putting upward pressure on prices. Large numbers of European dealers flocked to our shores and millions of dollars of European stamps flowed back to their countries of origin.
Beginning in the 1980s (with Japan) and the 1990s (with China) similar market forces made for price rises and repatriation of philatelic property. Today we have a stamp market that is truly international. Stamps largely sell to their highest market as informed buyers comb the world’s website looking for bargains
and what they need. Currency value even more than demand now has the potential to cause large price movements. The recent weakness for European stamps has largely been because of the weakness of the Euro. And many are betting that as the Chinese currency is revalued upward over the next few years that this should have a positive impact on the price of these stamps in dollars. Foreign currency markets influence the price of United States stamps too. Collecting US stamps is an important secondary specialty in China, Japan and Europe and when their currencies are strong we see a lot of stamps being sent overseas, reducing domestic supplies of new stamps for sale and raising prices.