NEW YORK (AP) _ U.S. investors responded less enthusiastically than their European counterparts Monday to Deutsche Telekom's first-ever sale of public stock amid concerns about the German phone monopoly's huge debt.

In the world's second-largest initial stock offering ever, Deutsche Telekom stock rose in Europe but slipped in New York from the opening price.

Deutsche Telekom's 600 million shares were initially priced at 28.50 marks ($18.89), making the offering worth $11.33 billion. The stock rose 2 percent on the Frankfurt Stock Exchange from its opening of 33.20 marks ($22.12).

But on the New York Stock Exchange, where 14 percent of the deal was sold, the company's American depository receipts were trading at $21.50 at late afternoon as the most active issue. The shares opened at $22.

Deutsche Telekom will use proceeds from the deal to pare about 20 percent of its $64 billion in debt, run up in recent years by installing telephone service in eastern Germany following its unification.

The deal's value is second in size only to the $12.4 billion raised by British Petroleum's initial public offering in October 1987, according to Securities Data Co. It also was the second-largest offer ever by a foreign company on the NYSE, also just behind BP.

The deal's promoters called the stock sale a momentous event, signaling the transition of an old-line European monopoly into an investor-fueled telecommunications powerhouse.

Ahead of the NYSE's opening bell, company and exchange officials gathered for an audio-visual show in front of the exchange's Broad Street headquarters in downtown Manhattan.

Giving a flavor for the company's global potential, a long screen beamed images of a surrealistic Earth in space, cityscapes rising from flat ground, and finally, the words, ``Here we are,'' as the sun rose in the background.

``Today is an historic day,'' said NYSE chairman Richard Grasso at a breakfast briefing at the NYSE headquarters.

Telekom, the world's third-largest telecommunications firm, initially planned to offer 500 million shares, but this month raised that to 690 million because of strong interest in Germany. The proceeds could climb if the company's underwriters, as expected, exercise an option to sell an additional 90 million shares by year's end.

By paring its debt, Telekom is preparing for 1998, when Germany's telecommunications market will be fully opened to competition.

Analysts predict the stock will rise in the short term, but are divided over Telekom's long-term prospects.

The company has long been criticized for poor customer service and sluggishness in updating its network with such late 20th century technology as touch-tone calling. It also is saddled with bloated staffing as well as debt from rewiring eastern Germany.

Telekom chairman Ron Sommer emphasized things would change.

``We have undertaken to become the most customer-friendly and competitive supplier in our branch,'' Sommer said in Frankfurt.

Telekom has bombarded the public for months with ads offering discounts and bonuses in an unprecedented campaign to persuade Germans to buy the stock.

The appeal seems to have worked: 3 million Germans called a special hotline for information, and 1.4 million of them ordered stock, the company said.

Heinz Gerlach of the National Association of Private Capital Investors in Germany said that advertising campaign may have led small investors to believe the stock was risk free.

``The course will naturally go up at first,'' but there could also be a quick fall, he cautioned.