benefits relating to excess stock-based compensation deductions are presented as financing cash flows. Cash inflows from tax benefits related to stock-based compensation deductions were $78 million , $429 million , and $62 million in 2013 , 2012 , and 2011 . 

In 2013, 2012 , and 2011 we recorded net tax provisions of $161 million , $428 million , and $291 million . Except as required under U.S. tax law, we do not provide for U.S. taxes on our undistributed earnings of foreign subsidiaries that have not been previously taxed since we intend to invest such undistributed earnings indefinitely outside of the U.S. If our intent changes or if these funds are needed for our U.S. operations, we would be required to accrue or pay U.S. taxes on some or all of these undistributed earnings. As of December 31, 2013 , cash held by foreign subsidiaries was $4.6 billion, which include undistributed earnings of foreign subsidiaries indefinitely invested outside of the U.S. of $2.5 billion . We have tax benefits relating to excess stock-based compensation deductions and accelerated depreciation deductions that are being utilized to reduce our U.S. taxable income. Accelerated depreciation deductions on qualifying property were a result of U.S. legislation that expired in December 2013. As such, cash taxes paid (net of refunds) were $169 million , $112 million , and $33 million for 2013 , 2012 , and 2011 . As of December 31, 2013 , our federal net operating loss carryforward was approximately $275 million and we had approximately $295 million of federal tax credits potentially available to offset future tax liabilities. The U.S. federal research and development credit expired in December 2013. As we utilize our federal net operating losses and tax credits, we expect cash paid for taxes to significantly increase. We endeavor to optimize our global taxes on a cash basis, rather than on a financial reporting basis. 

Our liquidity is also affected by restricted cash balances that are pledged as collateral for standby letters of credit, guarantees, debt, and real estate lease agreements. As of December 31, 2013 and 2012 , restricted cash, cash equivalents, and marketable securities were $301 million and $99 million . To the extent we process payments for third-party sellers or offer certain types of stored value to our customers, some states may restrict our use of those funds. This restriction would result in the reclassification of a portion of our cash and cash equivalents from “Cash and cash equivalents” to “Accounts receivable, net and other” on our consolidated balance sheets. See Item 8 of Part II, “Financial Statements and Supplementary Data—Note 8—Commitments and Contingencies” for additional discussion of our principal contractual commitments, as well as our pledged assets. Purchase obligations and open purchase orders, consisting of inventory and significant non-inventory commitments, were $4.4 billion as of December 31, 2013 . Purchase obligations and open purchase orders are generally cancellable in full or in part through the contractual provisions. 

On average, our high inventory velocity means we generally collect from consumers before our