Resolves to whomever Trump formally endorses FIRST in the Texas Senate Republican primary.

If Trump simultaneously (or within the same event/day/news cycle/leak/whatever) endorses multiple candidates, this resolves equal parts to all of them. So, I will probably hold off resolving for a few hours after the endorsement if there's any uncertainty to make sure that Trump actually meant it and didn't mean to formally endorse, say, 2 or 3 candidates. So you probably shouldn't immediately bet the option up to 99.9%.

If Trump makes no formal endorsement by the primary election on March 3rd, then this resolves to "No One".

If Trump endorses someone who is not an option, this resolves to "Other". If Trump simultaneously endorses, let's say, 2 ppl on this list and 3 ppl not among the options, it would resolve 20% to each of the 2 ppl on the list and 60% to other (this is probably not going to happen though).

I will not bet in this market to remain objective over what constitutes a formal endorsement (after an initial adjustment to reasonable market probabilities).