In line with the commitment to bolster the Group’s financial structure, measures continued to be taken in 2017 to reduce debt and improve the Group’s credit rating (in the case of S&P, the rating improved from BBB- to BBB with a stable outlook; for Moody’s and Fitch, the outlook improved from “negative” to “stable”).
In line with its policy of financial prudence and its commitment to maintaining a high degree of liquidity, the funds held in cash by the Group at the end of the year and available credit lines amply exceed the maturity dates of its short-term debt.
The net debt at December 31, 2017 is €6,267 million, significantly lower than at the same date last year (€8,144 million), due to the improvement in the cash flow generated by the businesses driven mainly by the Upstream segment, discipline in investments and the lower costs of borrowing.
of net debt
Group liquidity, including committed and undrawn credit facilities, stood at €7,554 million at December 31, 2017, which is enough to cover its short-term debt maturities by a factor of 1.8. Repsol had undrawn credit lines amounting to €2,503 and 4,429 million at December 31, 2017 and 2016, respectively.
Average payment period to suppliers
The average payment period to suppliers for the Group's Spanish companies was 25 days in 2017, which is generated a cash flow the maximum 60-day limit stipulated by Law 15/2010, of July 5 (amended by final provision two of Law 31/2014), which establishes measures to combat late payment in commercial transactions. For further information, see Note 19 “Trade payables and other payables” of the 2017 consolidated financial statements.