United States. These undistributed earnings would be subject to U.S. income tax if repatriated to the United States. Assuming a full utilization of the foreign tax credits, the potential deferred tax liability associated with these undistributed earnings would be approximately $10.0 billion as of May 31, 2014 should the amounts be repatriated to the United States. The amount of cash, cash equivalents and marketable securities that we report in U.S. Dollars for a significant portion of the cash held by our foreign subsidiaries is subject to translation adjustments caused by changes in foreign currency exchange rates as of the end of each respective reporting period (the offset to which is substantially recorded to accumulated other comprehensive loss in our consolidated balance sheets and is also presented as a line item in our consolidated statements of comprehensive income included elsewhere in this Annual Report). As the U.S. Dollar modestly strengthened against certain major international currencies during fiscal 2014, the amount of cash, cash equivalents and marketable securities that we reported in U.S. Dollars for these subsidiaries decreased on a net basis as of May 31, 2014 relative to what we would have reported using constant currency rates from our May 31, 2013 balance sheet date.

The increase in cash, cash equivalents and marketable securities at May 31, 2013 in comparison to May 31, 2012 was due to an increase in cash generated from our operating activities, our issuance of $5.0 billion of senior notes in October 2012, and to a lesser extent, cash proceeds from fiscal 2013 stock option exercises. This increase was partially offset by $11.0 billion of repurchases of our common stock, $3.3 billion of net cash paid for acquisitions, the repayments of $1.7 billion of short-term borrowings pursuant to our expired revolving credit facilities, the repayment of $1.25 billion of senior notes which matured in April 2013, and the payment of cash dividends to our stockholders. Additionally, our reported cash, cash equivalents and marketable securities balances as of May 31, 2013 decreased in comparison to May 31, 2012 due to the general strengthening of the U.S. Dollar in comparison to certain major international currencies during fiscal 2013.

Days sales outstanding, which was calculated by dividing period end accounts receivable by average daily sales for the quarter, was 48 days at May 31, 2014 compared with 50 days at May 31, 2013. The days sales outstanding calculation excluded the impact of revenue adjustments resulting from business combinations that reduced our acquired cloud SaaS and PaaS obligations, software license updates and product support obligations and hardware systems support obligations to fair value.

Cash flows from operating activities:     Our largest source of operating cash flows is cash collections from our customers following the purchase and renewal of their software license updates and product support agreements. Payments from customers for these support agreements are generally received near the beginning of the contracts’ terms, which are generally one year in length. We also generate significant cash from