The iPath S&P GSCI Total Return Index ETN (Ticker: GSP) is linked to the S&P GSCI Total Return Index and provides you with exposure to the returns potentially available through an unleveraged investment in the contracts comprising the S&P GSCI plus the Treasury Bill rate of interest that could be earned on funds committed to the trading of the underlying contracts. The S&P GSCI Total Return Index is world-production weighted; the quantity of each commodity in the index is determined by the average quantity of production in the last five years of available data. The S&P GSCI contains approx. 24 commodities from all commodity sectors: energy products, industrial metals, agricultural products, livestock products and precious metals. S&P GSCI returns are calculated based on the arithmetic average of stable long positions in futures contracts. The index measures the returns accrued from investing in fully-collateralized nearby commodity futures. In order to avoid delivery and maintain a long futures position, nearby contracts must be sold and contracts that have not yet reached the delivery period must be purchased. This process is known as \"rolling"" a futures position. The index is a ""rolling index"". The index measures a fully collateralized commodity futures investment that is rolled forward from the 5th to the 9th business day of each month. "