it offers an opinion with no factual substantiation .... The expert must explain how he reached his conclusion.” Sparks, 232 S.W.3d at 863. Here, we conclude that Quinn’s opinion regarding LTC’s state of mind amounts to no more than nonproba-tive speculation. Although the unauthenticated documents attached to his affidavit do refer to LTC, the documents do not indicate on their face that LTC ever saw them, much less assented to any terms found in them. Quinn’s testimony about LTC’s understanding and intention based on those documents is mere speculation and guesswork, and it constitutes no evidence that LTC actually agreed to the “nonstacking endorsement” that U.S. Fire seeks to reform the policy to include. See Buis v. Fuselier, 55 S.W.3d 204, 209 (Tex.App.-Texarkana 2001, no pet.) (<HOLDING>). In sum, we hold that U.S. Fire failed to
holding that experts opinion on proximate causation amounted to no more than mere conjecture and speculation as to events surrounding accident holding that district court properly admitted property owners opinion testimony that was based on more than naked conjecture holding speculation insufficient to avoid summary judgment holding that speculation and conjecture cannot support an adverse credibility finding holding that experts opinion that doctor performed surgeries in order to avoid financial losses due to insurance deductibles was nothing more than conjecture and speculation