Note 3 - Offering of the Shares (iShares S&P Commodity-Indexed Trust [Member])

9 Months Ended

Sep. 30, 2013

iShares S&P Commodity-Indexed Trust [Member]

Note 3 - Offering of the Shares [Line Items]

Stockholders' Equity Note Disclosure [Text Block]

3 - Offering of the Shares                                             

Shares are issued and redeemed continuously in one or more blocks of 50,000 Shares in exchange for Index Futures and cash (or, in the discretion of the Sponsor, other Collateral Assets in lieu of cash). The baskets of Index Futures and cash (or, in the discretion of the Sponsor, other Collateral Assets in lieu of cash) are transferred to or from the Investing Pool in exchange for limited liability company interests in the Investing Pool. Prior to April 8, 2013, the Investing Pool was required to deposit cash margin with its futures commission merchant (its "Clearing FCM") with a value equal to 100% of the value of each Index Future position at the time such position was established. As a result of certain amendments to the CME rules for the Index Futures that became effective on April 8, 2013, the margin requirements applicable to certain market participants, such as the Investing Pool, were replaced with the initial and variation margin requirements applicable to other market participants. Collateral Assets not held at the Clearing FCM are held in the Investing Pool's accounts.

Individual investors cannot purchase or redeem Shares in direct transactions with the Trust. The Trust transacts only with registered broker-dealers that have entered into a contractual arrangement with the Trust and the Sponsor governing, among other matters, the creation and redemption of Shares (such authorized broker-dealers are the “Authorized Participants”). Authorized Participants may redeem their Shares (as well as Shares on behalf of other investors) at any time on any business day in one or more blocks of 50,000 Shares. Redemptions of Shares in exchange for baskets of Index Futures and cash (or, in the discretion of the Sponsor, other Collateral Assets in lieu of cash) are treated as sales for financial statement purposes.

On September 30, 2013, the Trust had 39,350,000 Shares outstanding.