28 Contingent liabilities, encumbrance of assets and other commitments
At December 31, 2017 and 2018, the Group had no significant contingent liabilities to third parties, and none of the Group’s assets were pledged, assigned or subject to retention of title, except for the following positions:
Land and buildings (classified as held for sale)
Purchase commitments – In the ordinary course of business, the Group regularly enters into relationships with suppliers whereby the Group commits itself to purchase certain minimum quantities of raw materials for the manufacturing of its products in order to benefit from better pricing conditions and a stable supply. Such commitments reflect normal business operations, are in line with the Group’s manufacturing plans and product life cycles and are not in excess of current market prices. The Group recognizes a provision for onerous contracts if and to the extent such commitments exceed the Group’s expected purchase quantities. At December 31, 2018, the purchase commitments amounted to CHF 105.7 million.