The share price slump of JJB Sports has proved a drag on the net asset value (NAV) per share of Crystal Amber Fund, the activist fund that specialises in taking positions in what it regards as undervalued companies.The investment company, which has representation on the board of JJB after being actively involved in the struggling sportswear retailer's refinancing, saw its NAV per share dive to 101.92p at the end of 2010 from 115.50p at the end of June.Crystal Amber is pinning its hopes on turnaround specialist Mike McTighe, JJB's new chairman, to revive the fortunes of the chain and claimed that the bid approach for JJB from High Street competitor JD Sports "suggests that rival retailers see the recovery potential of the business.""Clearly the issues affecting JJB have become more challenging, but we remain convinced that there is potential, which is why we played a leading role in discussions leading up to its recent fundraising and board changes," said the company's chairman, William Collins. Things are going better at the fund's second largest holding, the electronic payment services provider Paypoint, whose share price received a shot in the arm in the first week of March when the National Lottery Commission rejected a plan by lottery operator Camelot to sell other services such as mobile top-ups and bill payments through its terminals.The fund was fully invested for much of the second half of 2010, although the successful realisation of investments enabled it to maintain a healthy cash position by the end of the period.At 31 December 2010, equity holdings represented 93% of total assets, and cash and liquid resources were in excess of £4.4 million.Income in the six months to end-December dipped to £1.0m from £1.3m the year before, while the return for the period was a loss of £8.1m, versus a gain of £5.5m the year before, largely as a result of a £9.1m downshift in the value of the fund's portfolio.