NEW YORK--(BUSINESS WIRE)--Halper Sadeh LLC, an investor rights law firm, is investigating whether the sale of PROS Holdings, Inc. (NYSE: PRO) to Thoma Bravo for $23.25 per share in cash is fair to PROS shareholders. Halper Sadeh encourages PROS shareholders to click here to learn more about their legal rights and options or contact Daniel Sadeh or Zachary Halper at (212) 763-0060 or sadeh@halpersadeh.com or zhalper@halpersadeh.com. The investigation concerns whether PROS and its board of direc. ...