Mr. Einhornâs request to the S.E.C. for confidential treatment illustrates the zealous approach some managers in the $2.7 trillion hedge fund industry take when it comes to keeping their trading positions out of the public eye. But it also reflects the risk that can come with being a money manager like Mr. Einhorn, who has cultivated press coverage over the years when it suits his interests.
In support of its request, Greenlight attached several news articles describing how prices of stocks often rise or fall sharply on reports that Mr. Einhornâs firm is either buying them or betting that they will fall. The firm, which has $10 billion in assets under management, offered the articles as proof that a premature disclosure of its buying strategy on Micron would cause âsubstantialâ financial harm to its investors because the hedge fund intended to keep accumulating shares for at least another week.
The regulatory filing for which Mr. Einhorn requested confidential treatment is called a Form 13F. It is filed 45 days after the end of a quarter to provide the investing public with a snapshot of a managerâs holdings of United States stocks. The S.E.C. seldom grants requests by investment managers for confidential treatment, but because it can take weeks, or even months, for a request to be reviewed, a manager gets the benefit of the doubt to keep a position secret simply by asking regulators to consider it.
The 10-page letter, portions of which were redacted by the S.E.C., glosses over the fact that Mr. Einhorn has never been shy about speaking about his firmâs stock holdings at charitable events and conference calls â" as he did on a call last year when Greenlight proposed that Apple use some of its $137 billion cash reserve to issue a dividend-paying preferred class of stock.
The redacted letter does not mention that the seven-day window of secrecy was set to expire on the same day that Mr. Einhorn planned to appear at a charitable event in New York City where he was supposed to unveil his âbestâ investing idea. It was at that Nov. 21 investors conference, sponsored by the nonprofit Robin Hood Foundation, where Mr. Einhorn first disclosed that his fund had taken a big equity stake in Micron.
Mr. Einhornâs presentation, giving a bullish case for Micronâs stock, caused a big splash at the event, which was attended by other prominent hedge fund managers. On the same day Mr. Einhorn spoke at the Robin Hood conference â" he is the foundationâs vice chairman â" he also appeared on the cable business channel CNBC to discuss his views on Micron.
By the close of trading on Nov. 21, shares of Micron had jumped 6 percent, with most news outlets crediting Mr. Einhorn, 45, with pushing the shares higher.
Paul G. Hodgson, a principal at BHJ Partners, a corporate governance consulting firm, said money managers like Mr. Einhorn were taking advantage of what he called a âloopholeâ that has long existed in the confidential treatment process that enables them to keep positions secret until the S.E.C. decides on the request. He said managers might be less inclined to take advantage of the loophole if the S.E.C. moved faster in reviewing requests.
âIt is a little hypocritical of money managers to exploit that loophole because they want press attention when it serves their interests,â Mr. Hodgson said.
The S.E.C. declined to comment on Greenlightâs confidential treatment request.
Last fall, the S.E.C. issued guidance to money managers advising them that requests for confidential treatment âshould demonstrate the likelihood of substantial harmâ and provide specific examples.
Jay G. Baris, a partner in New York with the law firm Morrison & Foerster, said that in recent years the S.E.C. had become âmuch more sensitiveâ about requests for confidential treatment from money managers, but he added, âthere are legitimate reasons to request confidentiality.â
Jonathan Gasthalter, a Greenlight spokesman, declined to comment. But Mr. Gasthalter pointed to a comment made a year ago by Mr. Einhorn in which the money manager cautioned investors to do their own work and not âblindly follow me or anyone else into a stock.â
Mr. Einhornâs request to the S.E.C. for confidential treatment probably would have gone unnoticed if not for a lawsuit he filed earlier this year to learn the identity of an anonymous blogger on the financial website Seeking Alpha, who wrote a post last November suggesting Greenlight was taking a big stake in Micron. The post was published the same day that Greenlight sent its letter to the S.E.C. seeking confidential treatment.
In March, Mr. Einhornâs firm dropped the suit after it said it had learned the identity of the blogger, and presumably the person who leaked the information about Micron. The identity of the blogger, known as Valuable Insights, has not been made public.
Greenlightâs investment in Micron has proved to be one of Mr. Einhornâs better performing trades. Shares of Micron are up 32 percent since Mr. Einhornâs presentation at the Robin Hood conference.
On Monday, Mr. Einhorn, whose fund is up 3.2 percent for the year, will once again take to a public forum to present some of his best investing ideas. He is scheduled to speak at another annual charitable event, held by the Sohn Conference Foundation, during which top money managers present their best ideas to a crowd of wealthy investors who pay thousands of dollars to attend. Other speakers at the Sohn conference will include the money managers William A. Ackman, Jeffrey Gundlach and Paul Tudor Jones II, founder of the Robin Hood Foundation.
The Sohn conference, which raises money for pediatric cancer treatments and is named after the hedge fund trader Ira Sohn, who died of cancer at 29, is one of the signature events for hedge fund managers to present their best trading ideas.
In 2008, Mr. Einhorn rocketed to hedge fund stardom when he used the conference to take on Lehman Brothers and criticize its accounting practices â" months before the firm collapsed at the height of the financial crisis. In December 2012, at a special Sohn conference, Mr. Ackman unveiled his $1 billion short position on the nutritional supplement manufacturer Herbalife, which has made headlines for the last 18 months.
âI guess it is all playing the press. They all do it,â said Mr. Hodgson, commenting on hedge fund managers going public with their trades. âIt is their modus operandi, and it tends to be very effective.â
A version of this article appears in print on 05/05/2014, on page B1 of the NewYork edition with the headline: Hedge Fund Asks S.E.C. To Delay Disclosures .