Dallas-based financial services firm HFF, Inc. (NYSE: HF) is seeing its stock soar in response to earnings released after close of trading Wednesday. HFF shares were up 12% as of 1:10 p.m. EDT on Thursday.HFF reported 18.1% year-over-year growth in revenue at $138.8 million for its first fiscal quarter. Earnings per share were $0.50, a 39% improvement from last year's Q1.Both numbers were superior to what Wall Street had predicted.