CIBC (CM.TO) may be forced to sweeten its US$4-billion takeover offer for Chicago-based PrivateBancorp (PVTB.O), now that U.S. regional bank stocks have rallied in the wake of Donald Trump’s U.S. election victory, according to a research report from Canaccord Genuity.

The CIBC-Bancorp deal faces a shareholder vote on Dec. 8, but the purchase is no longer a “given,” Canaccord Analyst Gabriel Dechaine wrote.

“Over the past week, two activist shareholders and two proxy advisory firms (ISS, Egan Jones) have recommended [Bancorp] shareholders to vote against the transaction,” Dechaine said.

“As a result, we believe the probability of [Bancorp] shareholders voting against the transaction has increased and, therefore, that [CIBC] faces a decision to potentially sweeten its original offer.”

Since CIBC announced the cash and stock deal in June, PrivateBancorp shares have surged about 30 per cent. The stock is currently trading at US$50.36 a share, compared to CIBC’s original US$47 per share offer price.

In an emailed statement to BNN, CIBC said on Tuesday that it remains committed to its current offer for PrivateBancorp. 

"We remain fully committed to this transaction and the offer we have on the table, which we continue to believe provides clear strategic benefits and offers stockholders of Private Bank the certainty of a significant cash payment, as well as the opportunity to participate in the future growth and value creation of the combined company," a CIBC spokesperson said.

Still, raising its Bancorp offer may pay off in the long term for CIBC, according to Dechaine.

“With a steepening yield curve, potential for stronger U.S. economic growth and the possibility of lower U.S. corporate taxes and a lighter regulatory burden, [CIBC] might generate more upside from [Bancorp] than we initially imagined,” Dechaine said. 

A sweetened offer may still be cheaper than what could happen in the long run, as Dechaine noted the price tag for U.S. regional bank stocks may continue to rise.

When it announced the deal in June, CIBC said the Bancorp acquisition would help it signficantly expand its reach in North America. Bancorp has about 1,200 employees and a presence in 12 U.S. markets.