210/264 Notes to the 2017 consolidated financial statements revenues, depending on the risk hedged, when the hedged transactions are settled. If the hedged transactions become probable of not occurring, the corresponding amounts in other reserves are immediately reclassified to finance income or costs. Foreign exchange forward contracts that do not meet the requirements in IAS 39 Financial Instruments to be designated as a cash flow hedge, are classified as derivative instruments not designated for hedging. The Group measures these instruments at fair value with changes in fair value recognized in finance income or costs. Refer to Note 22. (s) Cash and cash equivalents Cash and cash equivalents comprise cash on deposit at banks and on hand and short term deposits with a maturity of three months or less from the date of purchase that are not subject to restrictions. Cash deposits that have restrictions governing their use are classified as restricted cash, current or non­ current, based on the remaining length of the restriction. The Group classifies highly liquid investments with maturities of three months or less at the date of purchase as cash equivalents. For the purpose of the consolidated statement of cash flows, cash and cash equivalents consist of cash and short term deposits as defined above. (t) Short term investments The Group invests in a variety of instruments, such as commercial paper, money market funds, corporate debt securities, collateralized reverse purchase agreements, and government and government agency debt securities. Part of these investments are held in short duration fixed income portfolios. The average duration of these portfolios is two years. All investments are governed by an investment policy and are held in highly­rated counterparties. Separate credit limits are assigned to each counterparty in order to minimize risk concentration. These investments are classified as available for sale securities and are carried at fair value with the unrealized gains and losses reported as a component of equity. Management determines the appropriate classification of investments at the time of purchase and reevaluates the available for sale designations as of each reporting date. The available for sale debt securities with maturities greater than twelve months are classified as short term when they are intended for use in current operations. The cost basis for investments sold is based upon the specific identification method. (u) Long term investment Long term investment consists of a non­controlling equity interest in a private company. The investment is classified as an available for sale financial asset and carried at fair value through other comprehensive income. Refer to Note 22. (v) Share capital Ordinary shares are classified as equity. Equity instruments are initially measured at the fair value of the cash or other resources received or receivable, net of the direct costs of issuing the equity instruments. For the years ended December 31, 2012, 2013, and 2015, the Group issued equity instruments that were part of a compound transaction whereby additional shares would be issued to the shareholders upon the occurrence of F­17