(ShareCast News) - Tanfield, a passive investment company, reported a loss before tax for the year ending 31 December 2015 after it wrote down the value of one if its investments.Tanfield's pre-tax loss before impairments widened from £389,000 in 2014 to £4.4m for the year ending 31 December 2015, due to impairment charges of £4.8m.The company held two passive investments: 5.76% in Smith Electric Vehicles and 48% in Snorkel International Holdings, an aerial work platform manufacturer.Tanfield had owned Snorkel since its disposal in October 2013. Its current beneficial owner, Don Ahern, the owner of Extreme and Ahern Rentals, which owns 51% (with Tanfield owning the rest), has invested over $70m since the disposal.The company said Snorkel intended to focus on improving profit margins of its products through procurement synergies and standardisation across the product range as well as efficiency improvements. In March 2016 Ahern Deutschland, the German distributor for Snorkel, opened a €1.1m headquarters to increase European market penetration.Snorkel was valued at £36.3m (or $60.1m, being $43.1m equity holding and $17.0m preferred interest holding).Smith, however, was in the middle of legal proceedings with FDG Electric Vehicles due to alleged "fraudulent misstatements" by Hong Kong-listed FDG and a proposed new joint venture. Smith filed the complaint in May 2016.The Board of Tanmen decided that the investment value of Smith, which was valued at £4.8m in 2014, should be reduced to nil. Tanfield said in a statement, the company has decided to impair Smith's investments to nil due to the uncertainty around the level of funding required before Smith is able to achieve profitability and become self-financing and the disruption, costs and delays as a result of the disagreement with FDG.It also said it would continue to monitor any progress made by Smith and will review the position should significant progress be made.Smith had since focused on the sale and production of its existing vehicles in the US and European markets and was continuing to looking for joint venture or partnership opportunities in the rest of the world.The manufacturer of zero-emission commercial electric vehicles was also seeking to raise $15m in new funding through a series F financing round. Tanfield said that it was "unknown at this stage whether this financing will be successful or not".Chairman Jon Pither said: "During the year we have continued to monitor the progress of both investments closely. The board feels that some progress has been made towards a realisation in value of the investment in Snorkel following further growth in 2015."The board does not feel that sufficient progress was made by Smith and, following a review of the investment in Smith, decided to impair the investment to a nil value. The current combined value per share of investments is 27p per share."Tanfield's shares were down 6.98% to 10p at 1348 BST.