(Reuters) – T. Rowe Price, NetSuite’s largest outside shareholder, said it would not tender its shares in Oracle‘s proposed acquisition of the U.S. cloud computing company, arguing the $9.3 billion deal undervalues it.

T. Rowe’s stance, disclosed in a letter to NetSuite’s board of directors made public on Wednesday, could put pressure on Oracle chairman Larry Ellison to consider putting forward a new offer in order to combine the software giant with NetSuite, in which he holds a 40% stake.

Oracle orcl said in July it had agreed to buy NetSuite for $109 per share in cash to bulk up its ability to help its corporate customers automate administrative operations. Its shares were trading at $109.30 on Wednesday afternoon, slightly above the agreed price, indicating some investors expected a new deal.

A majority of Netsuite n shareholders not affiliated with Ellison must tender their shares for the deal to happen. As the company’s largest shareholder after Ellison with an 18% stake, T. Rowe trow is in a position to significantly influence the outcome.

T. Rowe said in its letter it was disappointed NetSuite did not reach out to other potential buyers before agreeing on a price with Oracle.

“At $109 per share, our preference is for NetSuite to remain independent,” T. Rowe said.

It added potential bidders would probably avoid NetSuite because of Ellison’s “unique relationship with the company.”

“In our view, the inherent conflicts of interest between NetSuite, the Ellison entities and Oracle are daunting and may be impossible to manage,” T. Rowe wrote in the letter.

It is rare for a large mutual fund manager to intervene in such a public way. Most prefer to pressure corporate executives in private meetings, or to sell shares of companies whose strategy they question.

T. Rowe has been the occasional exception to this convention. In 2013, for example, it opposed Michael Dell’s deal to take his eponymous computer maker private.

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Shareholders can pursue legal action if they believe a deal undervalues their company, provided they do not tender their shares. Dell had to pay tens of millions of dollars to shareholders following such a lawsuit.

T. Rowe, however, said it appreciated some conditions NetSuite put into place, such as the minimum acceptance threshold in the tender offer. NetSuite also formed a special committee of independent board members to consider the deal.

T Rowe and NetSuite did not immediately respond to requests for comment on the letter.

This article has been updated with additional information