In early 2007, the publicly-owned railway in the Portugese city of Porto, Metro do Porto (MdP), entered into an exotic interest rate swap with the Spanish bank, Banco Santander (BST) that came to be referred to as a 'snowball' swap. This swap, along with similar swaps promoted by BST, would later become the subject of litigation when MdP and other counterparties defaulted on their obligations during 2013. Refer to page 155 of the Approved Judgement for precise details on the terms of MdP's swap, and in particular, how the 'spread' on the floating rate leg was determined. The 'spread' on the floating rate leg of the swap was related to three-month Euribor. Historical data on the level of this benchmark interest rate at quarterly intervals between 13 March 2009 and 13 December 2012 are as follows: