The National Association of Securities Dealers' regulatory arm Wednesday censured well-known short-seller Manuel Asensio and fined him and his firm, Asensio & Co., $75,000 for failing to properly record short sales and for making Internet message board postings that violated NASD regulations.

The action, which came in a settlement Asensio agreed to, also ordered the New York trader to hire a consultant to review his firm's policies on the use of the Internet related to securities, and short-selling.

Asensio neither admitted nor denied the charges, which is typical for such settlements. But it quickly became clear that the agreement between him and NASDR to put the matter to rest was only on paper.

Asensio, in an interview, called the charges "hyper-technical" and said the NASDR action was retribution for allegations he brought to

Congress

and other regulators of improper listing at the

American Stock Exchange

, which is owned by the NASD.

"It's entirely an attempt to silence a whistleblower," Asensio said. "We simply settled to get them off our backs after 24 months."

The NASDR denied Asensio's claim that the charges were retaliatory.

"The violations in this case are based entirely on the actions of Mr. Asensio and his firm," said Barry Goldsmith, executive vice president of NASDR's office of enforcement.

Asensio & Co., the NASDR charged, failed to record more than 300 short-sale transactions as required, between Aug. 1, 1998 and July 31, 1999.

The company's Web site also failed to disclose risks associated with recommended short sales, the NASDR said. In addition, Asensio & Co. associates posted messages on Internet bulletin boards using aliases, failing to identify themselves as required by the NASD and in at least one case, misrepresenting themselves as not being affiliated with Asensio, NASDR charged.

Short-selling is a trading maneuver in which someone sells a stock he or she has borrowed, anticipating the price will fall, and then -- if things work as planned -- purchases the stock at a lower price, reaping a profit in the process. Short-sellers are notorious for attacking companies through the Internet and other means, hoping this will help drive down the share price of the firms' shares -- and make them money in return.

According to NASDR, which announced the fine and censure Wednesday, associates of Asensio's firm posted messages on Internet bulletin boards on

America Online

(AOL)

and

Motley Fool

in 1996 and 1997 that violated NASD rules.

The Asensio associates used such aliases as Xuanyal, Cruve66509, Flyrow and Twofour150, NASDR said.

One posted a message that read: "Asensio & Company's research is precise ... I have no affiliation with, and have no interest in Asensio or

the issue," according to NASDR.

The message postings were violations of NASD rules because Asensio failed to keep copies of the bulletin board postings on file. The NASD considers such postings "advertisements" and requires that copies be kept.

Goldsmith acknowledged it is rare for NASDR to bring such charges. "There have not been many cases, to date, dealing with message board postings," he said.

Asensio said NASDR's charges were "much ado about not much" and were really intended to pay him back for raising questions about alleged irregularities in listings at the Amex.

One of those charges concerned trading in shares of

Hemispherx Biopharma

(HEB)

, a Philadelphia company with which Asensio has tangled in court and in

news stories for months.

Asensio acknowledged Wednesday that some of his clients currently hold short positions in Hemispherx.

Asensio said he brought the allegations about what he considered irregular Amex listings and stock fraud first to Amex, then to the

Securities and Exchange Commission

, and then to Rep. John Dingell, D-Mich., a member of the House Commerce Committee.

Dingell earlier this month asked the

General Accounting Office

, the investigatory arm of Congress, to look into the allegations.

Goldsmith dismissed Asensio's claim that the disciplinary action NASDR brought Wednesday concerned trivial matters.

"All of the rules involved in this case have important purposes," he said.