According to F1.com's Lawrence Barretto, Haas's decision was fuelled mainly by a running out of patience, particularly expressing frustration over the disappointing outcomes of the $8 million upgrade revealed at the United States Grand Prix in Austin.
"To take advantage of that allowance and improve their own capabilities that are trailing rivals in the short-term, they would need Gene Haas to spend his own money," he wrote.
"He did just that for the big upgrade package introduced in Austin last year. Sources say that cost around $8 million. The results were disappointing, with Nico Hulkenberg even reverting to the old spec, which turned out to be faster.
"The disappointment of the big and expensive upgrade irritated Gene Haas for obvious reasons. It wouldn’t be a surprise, then, if he is reluctant to put his own money on the table once again.
"The topic of investment – and how change was needed because something wasn’t working – is likely to have been a central point of discussions when he met with Steiner for their regular winter catch-up to review how the team was doing and what the future looked like."