SWAG is an asset class comprising silver, wine, art and gold, identified by economist Joe Roseman in his 2011 Investment Week article, "SWAG: The Industry's Latest Acronym". He describes these as transportable and easy to store physical assets with no income stream (and so no exposure to income tax) and no incumbent debt, whose performance appears unrelated to the performance of equity markets; and he notes that none of these factors would be affected by sovereign default. Because of their scarcity, desirability, durability and stability and the independence of their price from stock market prices they can add genuine diversity to an asset portfolio.