Editor's Note: In this feature from Stockpickr , we highlight lists of stocks that have made new highs, lows or seen other unusual activity.Biggest % Gainers: Local.com ( LOCM) surged more than 45% after media company Hearst Communications reported a 22.4% stake in the search-engine operator, or about 2.7 million shares. The stake newly reflects warrants to purchase around 1.2 million shares, which weren't included in Hearst's April ownership filing because they had replaced old warrants for an identical amount of shares. In a March filing, which reflected the old warrants, Hearst reported 22% ownership in the company. Shares closed up $4.06 at $12.93. Biggest % Losers: Dallas-based Penson Worldwide ( PNSN) plunged 25% Thursday after the asset manager reported a weak quarter and as a result cut its full-year outlook. Even though the company announced a $25 million buyback plan, shares fell $6.25 to $19.11 in heavy trading. 52-Week Highs: Hilton ( HLT) shares rocket 26% after announcing it would sell itself to Blackstone ( BX) for $20.1 billion. The hotel operator gained $9.34, reaching a 52-week high of $45.39. 52-Week Lows: Beazer Homes ( BZH) sank to another 52-week low of $23.07. In Thursday trading shares lost 37 cents, or 1.58%. Late last month, the company fired its chief accounting officer "due to violations of the company's ethics policy stemming from attempts to destroy documents." Rising on Unusual Volume: Amid three times average volume, Synchronoss Tech ( SNCR)gained 5.6% Thursday. Synchronoss, which helps telecoms and other companies process orders with software, closed up $1.04 at $34.90. Stocks with Unusual Option Activity: Verizon Communications ( VZ) was experiencing unusual options activity. Shares closed down half a percent, or 14 cents, at $41.98. /> Latest Activist Situations: In an amended 13D filing on Vitesse Semiconductor ( VTSS), 6.3% holder Chapman Capital informed the company's management that they intend to submit to the SEC a Schedule 14A commencing a process of soliciting proxies to replace the board of directors.