u/z corn is tightening because farmers refuse to sell grain and end users are buying up on this price break hence causing a tightening basis and a tightening spread. Absolutely ridiculous why its happening but as long as farmers hold tight that spread will stay tight. However I believe the puke point for farmers is after the wednesday report, they are banking on that as their last hope for a rally in flat price but regardless of if they get the rally or not they will sell grain (have to move a huge old crop carry over in order to take on a record crop)
u/z wheat blowing up lately because everybody and their mother is short, thats the only reason. Also I would have to say there is some government presence or CME Group itself pushing in the spread so they don't have the CFTC on their ass and the world doesn't realize that the contract is broken, but thats just a conspiracy theory.