O.I. Corp ( OICO) sank on news that it will conduct an internal review of its historical stock-option grants. During the probe, the Texas-based maker of chemical-analysis products will halt its stock buyback program. President, Chairman and Chief Executive William Botts will be put on voluntary paid leave along with VP and Corporate Secretary Jane Smith. Four high-level employees and board members are to assume the vacated roles. O.I. also warned that it might be late with its year-end report if the probe uncovers "significant" issues. Shares were falling $1.02, or 9.2%, to $10.13. Health care company Radiation Therapy Services ( RTSX) cut its earnings guidance for the fourth quarter to 30 cents a share, down from November's estimated range of 36 cents to 38 cents. The new total includes several items, the Fort Myers, Fla., company says, without which income would have totaled 36 cents. The revenue forecast was revised to $76 million to $78 million, up from $74 million to $77 million previously. Analysts are calling for $76.9 million on the top line. Shares were down $2.97, or 9.1%, to $29.71. Double Eagle Petroleum ( DBLE) fell after it reported "poor reservoir quality rock" in a Christmas Meadows Prospect well in northeastern Utah. The Casper, Wyo., company operates and currently owns roughly a quarter of the well, with its working interest soon due to increase to more than 30%. Shares were losing $1.51, or 6.5%, to $21.80. Hi/fn ( HIFN) was lower after the company widened its loss to $2.7 million, or 19 cents a share, in the quarter ended Dec. 31. The year-ago loss totaled $1.7 million, or 12 cents a share. Sales shrank 13% to $9.3 million. Shares were down 38 cents, or 6.7%, to $5.27.