Herbalife Ltd. (NYSE:HLF) was hit by another attack from Bill Ackman today as the hedge fund giant released a forty page manifesto renewing his attack on the company and reaffirming his earlier criticisms. Despite the behemoth attack, Herbalife stock is up by more than 3% today.

Why don’t investors care about Bill Ackman’s concerns?

Bill Ackman

Neither Bill Ackman nor Herbalife have changed their stance much since Ackman initiated his public short of the company on Dec. 19. Herbalife shares are down a grand total of 14% since the day before the short position was announced; however, the loss in value peaked on December 21. It’s been six weeks since the low in the shares, and investors are no longer listening to Bill Ackman.

There are several possible explanations for the failure of Ackman’s manifesto today. Herbalife investors may have become immune to the barrage being delivered by Bill Ackman. That’s the theory of Robert Chapman, founder of Chapman Capital Management. According to a quote he gave Businessweek, ““Like with a virus, Herbalife stock is becoming immune to Ackman’s bad medicine.”

Chapman of course has an economic incentive to extoll the virtues of Herbalife Ltd. (NYSE:HLF), he’s long the company and he has been for weeks. Investors going against Bill Ackman have been hoping the shares will skyrocket after Herbalife shakes off this drop. Many of the investors going long on the firm bought in at the lows just after Bill Ackman initiated his short.

Some of the more interesting questions that were asked in the manifesto included “Why does Herbalife have ATM machines in Mexico?”, and “Do the top 1% of Girl Scouts receive 88% of the badges?” The massive document pushes Herbalife from several different angles at once, including some unexpected ones.

The questions point to implications that Herbalife Ltd. (NYSE:HLF) is a pyramid scheme; that the company is laundering money, and that its accounting practices are obfuscating at best and purposefully misleading at worst. Bill Ackman says that the culture of transparency Herbalife executives talk about should allow them to answer those questions honestly and quickly.

Today’s release adds to some of the other color that has leaked into this debate. In late January Bill Ackman and Carl Icahn, who also appears to be long Herbalife, fought a deeply silly verbal battle on CNBC. Icahn refused to answer questions, claiming his interviewer was bullying him. The two investors argued over who had rejected the other as a friend, and who had tried to take advantage of the other a decade ago.

The Herbalife Ltd. (NYSE:HLF) short is the most exciting thing happening on Wall Street right now, and Bill Ackman is staking more and more of his reputation on it as each day goes by. The investors opposite Ackman on the trade are not risking as much as the maven in terms of reputation or assets.

Bill Ackman clearly needs to change his tack, the market no longer seems to be listening to his criticisms of Herbalife Ltd. (NYSE:HLF). If that continues he’s likely to lose massive value in assets, and even more on his reputation.