Shares of Salesforce.com Inc. tumbled 8% Wednesday after Mizuho analysts warned that an acquisition of Twitter could destroy up to 25% of Salesforce’s value.

Salesforce CRM, +1.11% has been rumored to be a potential buyer of Twitter, and there was increased speculation Wednesday after a Wall Street Journal story quoted Salesforce Chief Executive Marc Benioff as saying that Twitter is an “unpolished jewel.”

If Salesforce were to buy Twitter, Mizuho analysts said they believe the acquisition would wipe out $12 billion to $17 billion of Salesforce’s combined value with Twitter, or 20% to 25% of the company.

The acquisition would hurt Salesforce, Mizuho analysts say, because they believe the company would have to increase cash compensation to make up for high levels of stock-option expense used by Twitter, and would not derive short-term value from the acquisition.

“We did not assume any revenue or cost synergies in our calculation as they are completely different businesses and chances are that Salesforce.com might have to invest in it to drive growth,” the analysts wrote.

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It would take Salesforce two to three years to recapture that value, if the acquisition were to go well, they wrote.

Shares of Twitter TWTR, +7.09% were up 5% in Wednesday morning trading.

Still, analysts noted that even if Salesforce were to place a bid for Twitter, the company may face stiff competition from other rumored buyers, such as Walt Disney Co. DIS, +1.43% .

Read:Twitter must find a buyer before Snapchat destroys it

The Mizuho analysts reiterated a buy rating and $85 price target on Salesforce but cautioned investors about making a move into the stock while the company’s M&A intentions remain unclear.