When The Stock Market Magazine printed articles about companies to invest in, it neglected to tell readers the companies themselves paid for the stories and in some cases wrote them, the Securities and Exchange Commission charged yesterday.

The monthly magazine defrauded investors by failing to reveal how it got its stories and should have registered as an investment adviser, the SEC said.

Bernard D. Brown, managing editor of The Stock Market Magazine, denied the SEC's fraud charges and described the legal action as an assault on the publication's First Amendment rights.

The magazine, with approximately 50,000 subscribers, is put out by Wall Street Publishing Institute, Inc. Its publisher, Angelo R. Martinelli, is mayor of Yonkers, N.Y.

"We are a news magazine protected by the First Amendment to the Constitution. We aren't subject to the SEC's jurisdiction, but they don't agree with us. That's why they're bringing this action in court," Brown said yesterday.

Brown called the fraud charges "patently ridiculous" and without merit and said the company would defend itself against them. "We regard this as a fishing expedition," he said.

The "Voice of the Small Investor" since at least 1978 has carried stories analyzing small public companies and columns recommending the purchase of "penny stocks" and other low-cost securities, the SEC said.