A record-level stock market. Billionaire investor Warren Buffett maintaining in his annual letter that such price tags could indeed be justified.

Dramatic amounts being paid for individual New York Stock Exchange seats. Increased borrowing on margin by aggressive investors.Sure sounds exciting, but there are those who think all this actually signifies end times for the bull market.

In some cases, new technologies and brokerage demands for cost savings are changing the market's personality. That's the case with the move by the National Association of Securities Dealers to take over the American Stock Exchange. Such a combination offers companies the choice of having their stocks traded either on the Nasdaq electronic system or on the Amex floor.

But there's much more going on than organizational change these days, and some experts believe two recent events especially smack of speculation:

Big money is being paid to buy a piece of the action on the Big Board. An NYSE seat recently sold for a record $2 million, up $200,000 from the last sale in February. Back in the crash year of 1987, the highest price paid for a seat hit $1.115 million. In 1990, a seat commanded just $430,000.

There's been a fixed number of 1,366 seats since 1953. In order to get one, a seat must be put up for sale. That creates obvious demand in strong markets. Once purchased, only one person can fill each seat for the purpose of trading stocks.

Investors are increasingly borrowing to ride the bull market in stocks and bonds. There is $127.7 billion in margin debt outstanding, according to the Federal Reserve. That compares to $97.4 billion at the end of 1996 and $36.84 billion at year's end 1986.

You can borrow a maximum of 50 percent of the current value of the marginable securities in your account. Marginable securities are traded on the major U.S. exchanges that sell for at least $5 per share. Many over-the-counter stocks are marginable, as are most mutual funds.

"Both of those examples are evidence we're in early to middle stages of market speculation," contends Hugh Johnson, chief investment officer with First Albany Corp. in Albany, N.Y. "I'd add the fact that shares are changing hands like a hot potato, with the turnover ratio up to more than 70 percent."

The speculative nature of the situation, while troubling, isn't as intense as in the period before the crash of 1929, Johnson quickly added.

Others say some of these events aren't all that speculative.

"The NYSE seat selling so high is due to the terrific volume in which those seats really produce money," said John Markese, president of the American Association of Individual Investors in Chicago. "So it isn't necessarily speculation."

However, as far as margin debt is concerned, there's no question that most individuals who have common stock at 50 percent margin have doubled the risk of that stock they're investing in, Markese warned.

Margin trading is not something to be entered into lightly. The advantage is that you can generate higher returns by pumping borrowed money into the right stock. But if that stock heads south, you must sell quickly or you'll have to put more cash into your account and the brokerage firm will sell at least a portion of the stock as collateral.

The federal government and exchanges regulate margin accounts, the Fed determining whether stocks are marginable and setting maximum margin rates. Although investors may borrow up to half of the value of any marginable stock, only the biggest risk takers are willing to go that far out on a limb.

Some believe margin borrowing is no longer as big a worry as it once was.

"In the early 1980s, margin debt became a hybrid animal and no longer represented only equities on margin," pointed out Louise Yamada, technical analyst with Salomon Smith Barney and author of the book "Market Magic."

Brokerage firms have become total umbrellas for their clients' debt, Yamada said, especially institutional or banking clients to whom they can lend at a slightly lower rate than banks in order to try to attract more money to the brokerage house.

Another reason Yamada isn't worried about speculative fever is that she's convinced people are investing money seriously. Baby Boomers need a place for their dollars.

"One should never bet anything on just one indicator," she concluded. "The stock market is strong and intact."