The largest U.S. shareholder advisory firm recommended on Monday that Dell Inc stockholders vote in favor of Chief Executive Michael Dell’s $24.4 billion buyout offer, increasing the odds of his prevailing against billionaire investor Carl Icahn’s rival bid.

Dell shareholders are scheduled to vote on the offer July 18. Several large investors have been pushing for improved terms.

“The ISS seal of approval makes the Silver Lake/Michael Dell deal more likely to receive shareholder approval,” Brian White, analyst at Topeka Capital Markets said, adding that ISS views Icahn’s bid “as coming with too much uncertainty.”

Institutional Shareholder Services Inc is the biggest shareholder advisory firm, and its recommendations can sway investors looking for direction.

ISS on Monday said Michael Dell’s offer “transfers the risk of the deteriorating PC business and the company’s ongoing business transformation to the buyout group.”

It said shareholders cannot immediately accept Icahn’s bid even if they vote down Michael Dell’s proposed buyout.

Another proxy advisory firm Egan-Jones also put out a report on Monday supporting Michael Dell

Billionaire Carl Icahn and Southeastern Asset Management have made a rival bid that would see shareholders tender 1.1 billion shares at $14 each. But for the bid to be put to a vote, shareholders first must reject Michael Dell’s proposal and then elect a new slate of directors put up by Icahn.

“They must also vote to replace the entire board and the CEO through a proxy contest at a subsequent annual meeting, and even then may end up with cash and equity if the envisioned self tender is oversubscribed,” ISS said.