Robert Keebler, a certified public accountant with his own firm in Green Bay, Wis., said that in the first example, the large capital gain in a stock sets off the higher tax rates.
When James J. Cramer, the co-founder of TheStreet.com, went on TheStreet.com's cable television program and plugged TheStreet.com's own stock, he set off a battle over the ethics of stock promotion that may result in cancellation of the program.
The move pushed down the stock price, set off a dispute between Telekom and the bank and drew sharp criticism from shareholders.
They outpaced a broader decline in the stock market set off by investors' uncertainty about how the outcome of the presidential election will affect taxes and consumer demand for the types of products Apple sells.
But the Internet has opened up new ways to trade stocks and set off intense competition among different markets.
Analysts attributed the late surge to big institutional investors placing bets on stocks, which set off a wave of buying.
A Securities and Exchange Commission official said the agency was closely watching the cases where individual stocks had set off circuit breakers, but had found that each case had "its own story".
Analysts said the Treasury rally, as well as the selling in the European stock markets, was set off by new signs of weaker economic activity on the Continent.
Temasek said in February that the value of its investment portfolio fell 31percentt, or about $39 billion, from March to November, a reflection of the stock market rout set off by the turmoil surrounding American subprime mortgages.
The rally in American stock markets was set off by a report late Tuesday on the Web site of The Guardian, a British newspaper, that France and Germany had agreed to increase the size of the rescue fund — the European Financial Stability Facility — to as much as 2 trillion euros to contain the crisis and backstop Europe's banks.
