Stamp collecting is one of the world’s most popular hobbies, and involves collecting postage stamps and related items. There are estimated to be more than 20 million stamp collectors in the United States alone, and tens of millions more have stamp collecting as a hobby throughout the world. Although stamp collecting may be viewed as a form of investment, it is generally thought of as a hobby rather than an investment practice, simply because the value of the assets is thought to be fairly flexible.
The study of postage stamps, which should not be confused with stamp collecting, is known as philately. While some philatelists do engage in stamp collecting, many do not, treating stamps as objects of study and not objects of collection. At the higher levels of stamp collecting, however, most collectors do possess at least a moderate level of philatelic knowledge, as it is necessary for them to accurately assess the value and rarity of stamps they may be collecting.
While some postage stamps, especially those with printing errors, or those produced in very small amounts for commemorations, are worth a great deal of money, the vast majority are relatively affordable. This helps to contribute to the popularity of stamp collecting as a hobby, as it means that even those without a great deal of disposable income can acquire very old and historically important stamps, as they tended to be produced in sufficient numbers that enormous quantities still remain.
The Penny Black, for example, was the first postage stamp ever produced. It was issued in Britain in 1840 and has a portrait of Queen Victoria on it, and had to be cut out of a sheet before it could be used, as it had no perforations. In spite of the fact that the Penny Black is more than a century and half old, so many were printed and still exist that used stamps can be found for around $100 US Dollars (USD), with many examples available for $20 USD or less. While unused copies are still quite rare, and therefore more valuable, even they do not reach the exorbitant prices seen in many forms of collection.
One reason for the relatively low value of many stamps is that they are quite easy to store, and fairly easy to keep in mint condition. For example, during the 1920s many stamps issued in that time rose in value quickly, as they were quite rare, and collection was beginning to become a popular hobby. As a result, in the 1930s many collectors hoarded mint issues of stamps as they came out, hoping to capitalize on another quick surge in value, which of course, because of the large numbers kept in mint condition, never occurred. To this day, many of these popular stamps from the 1930s can be found in perfect condition at little more than the cost they were originally issued at.
Many tiny independent countries or dependencies have made national industries out of selling stamps to those who pursue stamp collecting as a hobby. In some cases, the sale of stamps may be one of the major sources of income for a country, even though the cost of these stamps is relatively low. Some famous stamps include the Treskilling Yellow, a Swedish stamp from 1855 with a color error, which sold for more than $2 million USD in 1990, and the Mauritius Post Office stamps, of which only five hundred of each of two colors were printed in 1847, and which sold for more than $4 million USD in 1993.