The phone call came just as the stock market opened yesterday. The caller told Dow Jones News Service he was a Cincinnati investor who was about to make an offer for Dayton Hudson Corp., the nation's sixth-largest department store operator.

Within minutes, the news service confirmed that the caller worked at a fund-management company and at 9:49 a.m. reported his takeover bid on its nationwide "ticker" that is closely followed by Wall Street traders.

The report quickly electrified the stock market. Trading in Dayton Hudson stock was halted abruptly by the New York Stock Exchange. Orders to buy the stock came pouring in to brokers offices; when trading resumed nearly two hours later, the price of the stock had climbed $6 to $59.25.

To many investors, the disclosure initially seemed very credible because Dayton Hudson has been an apparent takeover target of Washington's Haft family.

Then, at 12:39 p.m. -- an hour after trading in the stock had resumed, the Dow Jones wires moved a different version of the story: "Dayton Hudson offer cloudy, may not be bona fide." The offer, it turned out, was a hoax.

The rest of the day was spent sorting out the wreckage. Among other things, the stock dropped to close at $53, down $1 from the day before after more than 5.5 million shares changed hands. It was the second most active stock on the New York Stock Exchange.

The NYSE, meanwhile, said it has launched an investigation of the incident. After a six-week probe, it will decide whether to make the findings public or refer them to the Securities and Exchange Commission.

The SEC declined to comment yesterday.

The call to Dow Jones came from P. David Herrlinger, whom Dow Jones said was a prominent Cincinnati businessman who worked for a fund-management company. Herrlinger claimed to represent Stone Inc., which Dow Jones said was a private investment company for the Stone family, another well-known Cincinnati family. Herrlinger said Stone Inc. was offering $70 per share for all of Dayton Hudson's shares -- which would make the takeover worth about $7 billion.

After checking on Herrlinger's employment, Dow Jones reported Stone's offer.

The report came at the same time Dayton Hudson officials were testifying in hearings before a Minnesota state legislature committee asking for tighter antitakeover laws.

Concerned that a takeover bid from the Hafts was imminent, Dayton Hudson has asked that an emergency session of the legislature be called by the end of the week to make it harder for corporate raiders to buy any Minnesota firm.

Learning of the reported offer, Dayton Hudson's chairman Kenneth Macke urged the committee to act quickly. "By the end of the day, someone could have control and we could be gone by the end of July . . . believe me, I'm not trying to be alarmist," Macke testified.

Meanwhile, lending credence to its initial report, Dow Jones subsequently reported that a Dayton Hudson spokesman at the state legislature hearings had called the takeover "unsolicited." That report made it appear that the company had indeed received an offer.

Shortly after that report, trading resumed in the stock. While only 100,000 shares had changed hands before the trading was halted, minutes after trading resumed at 11:35 a.m., at least 655,000 shares were traded. Within two minutes, the stock price had climbed from the opening price of $53.25 to $59.25 on the New York Stock Exchange -- and even higher, to $63, on other markets.

Then, at 11:55 a.m., the offer slowly began to unravel, first with a clarification from Dayton Hudson, which said it had not received any takeover offer from Herrlinger or Stone Inc. At 12:39, Dow acknowledged that the offer is "cloudy, may not be bona fide."

Among other things, it turned out, there is no such thing as Stone Inc. in Cincinnati. There is, however, a company called Stone Interests, a private investment company for the prominent James H. Stone and his family. Stone is in the oil business.

Stone Interests was bombarded with calls from reporters yesterday shortly after the initial Dow Jones story broke. But secretary Joyce Stivers, speaking on behalf of the family, told reporters "The Stone family is not involved, period. . . . I have no idea where he came up with this. The family is just as much in the dark as you or I am."

Herrlinger, it turned out, was indeed a 46-year-old portfolio manager at a fund-management company -- at least until yesterday, when his boss fired him after overhearing his phone call to Dow Jones. "I happened to be walking past his office and heard him reading a statement to Dow Jones," said Richard Miller, president of the two-person office of Capital Management Corp. "When I found out he was affiliating the firm, that's where I had a problem and had to let him go."

Late yesterday, Herrlinger's neighbor, Anthony Covatta -- an attorney who was speaking for the Herrlinger family, said his wife had taken him to the hospital. "You've got a guy who's got some problems that have come on very suddenly," Covatta said.

"It looks to me like he got into a fantasy mode today. There's not much more to it that that. He's a lovely guy, just as plan as an old shoe. He loves to garden a lot -- there's nothing he likes better than to move his pine trees around his back yard. This is a terrible thing. A guy who's never owned a pair of Gucci shoes in his life does this," Covatta said.

Dow Jones New Service officials yesterday said they had no regrets about running the initial takeover report. "We don't feel we were had," said Everett Groseclose, managing director of Dow Jones News Service.

"There was no reason early on to question the veracity of the offer. We did confirm there was such an individual, and he worked where he said he did. When there is such a company that is engaged in money management and there is such an individual -- part of a wealthy family -- on the surface there doesn't seem to be any reason to question" the report," Groseclose said. What's more, he added the news service was "very efficient in smoking out that this was not a bona fide offer.

"Who knows how long it would have gone had we not continued to do the reporting we did," Groseclose said.

Throughout the day, the Haft family remained as mum as ever about their intentions for Dayton Hudson, standing by its "no comment" they had issued last week when the retailer revealed the Haft interest in the chain. Had the offer been real, however, the Hafts could have gained a substantial profit since they are believed to have bought a significant stake in Dayton Hudson in the high $40 to low $50 range.