X. I /A Table of Contents FIRST DATA CORPORATION NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS (Continued) Revenue Recognition The majority of the Company's revenues are comprised of: I) transaction-based fees, which typically constitute a percentage of dollar volume processed; 2) fees per transaction processed; 3) fees per account on file during the period; or 4) some combination thereof. In multiple-clement transactions, revenue is allocated to the separate units of accounting provided each element has stand-alone value to the customer. Stand-alone value is based on the relative selling price of any undelivered items for which delivery is probable and substantially within the Company's control. In the case of client contracts that the Company owns and manages, revenue is comprised of fees charged to the client, net of interchange and assessments charged by the credit card associations, and is recognized at the time the client accepts a point of sale transaction. The fees charged to the client are a percentage of the credit card and signature based debit card transaction's dollar value, a fixed amount or a combination of the two. Personal identification number based debit (PIN-debit) network fees are recognized in "Reimbursable debit network fees. postage, and other" revenues and expenses in the Consolidated Statements of Operations. STAR Network access fees charged to clients arc assessed on a per transaction basis. Interchange foes and assessments charged by credit card associations to the Company's consolidated subsidiaries and network fees related to PIN-debit transactions charged by debit networks arc as follows: Year ended December 31, (In mUllons) 2011 2013 2012 Interchange fees and assessments $20,406 $19,368 $18,373 Debit network fees 2,965 2,915 2,786 The Company charges processing fees to its merchant alliances. In situations where an alliance is accounted for under the equity method, the Company's consolidated revenues in