Wexford Capital opposes the proposed acquisition of the oil and natural-gas drill-rig supplier by Allis-Chalmers Energy (ALY). Wexford believes the deal isn't in the best interests of Bronco shareholders. Under the terms of the agreement, Bronco stockholders will receive $200 million in cash and 16.85 million shares of Allis-Chalmers common stock. The combined consideration values Bronco's shares at $18.25, based on the closing price of Allis-Chalmers' common on May 30. (Allis-Chalmers provides oil and natural-gas services, as well as equipment.) Wexford may communicate further with Bronco about the merger and may seek representation on the board. It would like to work with management on strategies to increase shareholder value. Wexford owns 3.37 million shares (12.85% of the total outstanding).

Jana Partners converted its filing status to activist investor, from passive. The hedge fund said it already has had "constructive dialogues" with executives of the human-resources systems provider on ways to improve shareholder value. Following Convergys' second-quarter earnings report, which included lowered '08 guidance, Jana determined "to reserve its right to take steps to bring about changes to increase shareholder value, which may include changes in the board composition, strategy and future plans of the company, as well as the pursuit of other plans or proposals." Jana holds about 12.2 million shares (9.9%).

Florida private investor Richard L. Scott reported owning 634,590 shares (7%) of the solar-cell component maker, having bought 287,013 from June 24 to July 28 at $8.95 to $9.50 each.

Money manager Steven A. Cohen raised his stake in the life-sciences company to about 6.17 million shares (6.9%), from the 4.8 million (5.2%) reported on July 1.

Trinad Capital Master Fund lifted its holdings in the interactive entertainment group to 5.83 million shares (10.5%), from the 4.93 million (8.8%) reported on June 25.

Springhouse Capital Master cut its stake in the Internet research firm by about 1.31 million shares (4.96%), from the 2.1 million (8%) reported on June 24.

Loeb Partners lowered its holdings in the restaurant group to 297,923 shares (8.28%), from the 341,223 (9.49%) reported on Jan. 17.

Van Den Berg Management reduced its stake in the asset manager to 10.07 million shares (19.75%), from the 10.46 million (21.98%) reported on June 23.