(Bloomberg) -- The gap between United States Steel Corp.’s stock price and a $14 billion proposed takeover by its Japanese rival exploded as traders ditched shares amid fears the deal will collapse under opposition from President Joe Biden.

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US Steel plunged as much as 24% triggering a volatility halt Wednesday after multiple reports suggested that Biden is preparing to block a planned sale to Nippon Steel. The stock closed at $29.38. That’s roughly 47% below Nippon’s $55-per-share offer, putting the deal spread at its widest level since the merger was announced in December.

Some merger arbitragers pointed out that the deal is still subject to a review by the Committee on Foreign Investment in the United States, throwing out some uncertainty on when the agency would finalize a decision and how that process would play out apart from Biden’s planned move.

“Is the President trying to pressure CFIUS into recommending the deal should be blocked? Usually, the President follows the CFIUS recommendation, not the other way around.” said Frederic Boucher, a merger arbitrage specialist at Susquehanna International Group. “Investors aren’t waiting for clarification and are exiting quickly.”

US Steel options volume surged to the highest since December Wednesday. January $35 and $25 puts, Sept. 20 and Oct. 18 $35 puts traded more than 10,000 contracts each.

--With assistance from David Marino.

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