THE WALL STREET JOURNAL.

By DAVID BENOIT And BEN FOX RUBIN

Carl Icahn on Wednesday pushed Dell Inc. shareholders to head to court to force Michael Dell to pay more, in the activist investor's latest effort to ruffle a buyout slated for a shareholder vote next week.

The billionaire investor has taken up the mantle of getting a Delaware judge to appraise the value of Dell, a ruling that could lead to those who join him getting more than the $13.65-per-share buyout—or possibly less. The decision to seek an appraisal suggests Mr. Icahn is resigning himself to the possibility shareholders vote for the buyout next week, as his plan would only affect shareholders if the deal passes.

At the same time, because a shareholder has to vote against the deal to seek an appraisal, if enough shareholders attempt the maneuver it could block the deal.

In Delaware, a shareholder is allowed to seek a judge's opinion on what the long-term intrinsic value of a company is, instead of outright accepting a merger offer. If a judge were to determine Dell shares are worth more than $13.65, the buyout group would be forced to deliver the extra amount, with interest, to those shareholders who sought the appraisal.

The shareholders also take the risk that a judge could rule the shares are worth less, and they would also have to wait the time it takes a judge to decide, potentially years. Also, owning appraisal rights could potentially be an issue for some institutional shareholders who have strict rules about holding only public shares.

Mr. Icahn wasn't immediately available for additional comment.

Mr. Icahn's plea to shareholders says "those who seek appraisal may get lucky" and presents the move as a can't-lose option because shareholders can withdraw their request up to 60 days after the merger and still get the $13.65 buyout price.

"We believe if you seek appraisal, you will receive more," the letter says.

Mr. Icahn, Dell's second-largest shareholder behind Mr. Dell, has repeatedly criticized founder Mr. Dell and private-equity firm Silver Lake Partners' offer to take Dell private for $24.4 billion, saying the group was undervaluing Dell's shares with its $13.65 per-share price tag.

Mr. Icahn revealed a position in Dell shortly after the buyout agreement was announced Feb. 5. In a recent filing, Mr. Icahn estimated his firm spent about $2 billion acquiring the position in Dell, which would mean an average of $13.12 a share. Part of his stake is in options, which makes his final cost unclear.

Dell shares were unchanged at $13.36 in midday trading in New York Wednesday.

Shareholder-advisory group Institutional Shareholder Services Inc. as well as Glass, Lewis & Co. and Egan-Jones Proxy Services this week recommended Dell stockholders vote for the buyout offer, improving the odds of the deal passing.

In his latest letter to shareholders, Mr. Icahn says those seeking appraisal can change their minds about that action up to 60 days after the merger. He says he would seek to settle the appraisal with Mr. Dell and Silver Lake, who have their own risk in any court proceeding, before that 60-day period, a situation he says may allow a shareholder to "have your cake and eat it too".

Gary Lutin and the Shareholder Forum, a shareholder-advisory group, set up a public trust earlier this year that would support Dell investors seeking appraisal rights and said Wednesday at least reserving an appraisal right seems a "no brainer" to many in the forum.

"Fair market value is almost always more than auction price, especially in a situation like Dell in which you have very sophisticated private-equity firms who are unlikely to pay more for a company than its professionally determined long-time going concern value," Mr. Lutin said.

Write to David Benoit at david.benoit@dowjones.com and Ben Fox Rubin at ben.rubin@dowjones.com