This page contains detailed information about Simon Groat as obtained and inferred through quests. It is organized by volume, and the quest(s) where the information was obtained is linked. If the quest was fealty-specific, that is noted as well.
Feel free to add new information as you find it!
If you have not played through all of the volumes, this post will contain spoilers.
Groat is momentarily startled when he mistakenly believes you are dissatisfied with his stealthier plots. Unquenched
No new information is obtained.
Groat is pleased with himself when he tells you that he thinks Alvyn is plotting against you, as if he thrives on reporting another's wrongdoing. A Little Night Commerce
He is either very happy that you punish Alvyn for worshiping R'hllor or very upset if you show him mercy. Light in the Darkness
Groat seems to be in charge of the hiring and commanding of rather unsavory individuals who deal in torture and butchery. The Elusive Murderer
He accuses Rona of framing him for treason because she has never liked him. Heads or Tails
He is from the Westerlands, natural with coin and very cunning, much like a Lannister. Hidden Fangs
Groat and Alvyn are both very successful tradesmen with very different temperaments. Hidden Fangs
He has been embezzling funds from your house. He has been diverting coin into his own pockets through secret taxes or smuggled goods. A Little Extra (Quest)
When confronted about his theft, he states he is a practical man, building his fortune while he can since he cannot rely on your house being around forever. He claims never to have stolen a coin from your counting house. The Confession
He would not be so kind if he was in your position; he would have beaten a confession out of someone like himself. The Confession If you choose to torture him, he approves of your decision. The Interrogation
If you choose to punish him by destroying his material possessions, he seems to take this worst of all. Sweet Revenge