Alan Booth, an Independent Non-Executive Director at FTSE 250-listed oil and gas group Ophir Energy, raised his holding in the company just a week after the firm disappointed the market with its first-half report.Booth, who was appointed to the board in April, is now one of four directors at Africa-focused Ophir who have raised their stakes since the results, taking advantage of the stock's recent slump to build positions and show confidence in their company. Since the results were announced on August 15th, the share price has fallen by over 20%.The company said on Thursday that Booth bought 25,000 on August 20th at a price of 306.5p each, spending a total of £76,625. He now holds 125,000 shares, equal to 0.021% of the company.Chief Executive Nicholas Cooper and fellow board-members Bill Schrader and Vivien Gibney have also raised their stakes in recent days; the latter only joined the board last week.While Ophir narrowed its pre-tax loss in the first half to $19.4m from $24.4m the year before, analysts said the negative share-price reaction was due to comments made about delays in finding suitable partners for future development programmes."The lack of concrete farm-out news is beginning to raise questions about industry interest and/or valuations in comparison with that ascribed by the market," said analysts at Canaccord Genuity last week.The stock has now slumped by nearly 40% since the start of 2013.Top Director BuysOphir Energy (OPHR) Director name: Mr Alan BoothAmount purchased: 25,000 @ 306.50p Value: £76,625JPMorgan Indian Inv Trust (JII) Director name: Mr Richard R J BurnsAmount purchased: 10,000 @ 301.60p Value: £30,160Land Securities Group (LAND) Director name: Mr Christopher BartramAmount purchased: 2,225 @ 890.00p Value: £19,802BC