Only one of the 10 companies with the most weight in Hong Kong's Hang Seng China Enterprises index, composed of so-called H shares, is still unavailable in Shanghai. And that company — China Communications Construction, a builder of ports — is the smallest in the group.

The others add up to 65 percent of the index's value, according to data compiled by Bloomberg. PetroChina has the highest weighting at 12 percent.

To put it another way, there aren't any companies left that would draw in mainland investors, generally confined to their home markets because of government restrictions, to the extent that PetroChina and its peers have done.

PetroChina's yuan-denominated A shares soared in Shanghai Monday, pushing the market value of the company, based in Beijing, to more than $1 trillion. No company worldwide had ever crossed that threshold before.

A revaluation of the government's 87 percent stake, held in the form of A shares, was largely responsible. Using the closing price on the mainland, rather than in Hong Kong, in calculations added $568.7 billion to the holding's value.

PetroChina is the 10th company in Hang Seng's H-share index to start trading on the mainland this year, and the surge in its market value produced some startling comparisons.

The company's capitalization exceeds that of Taiwan, whose publicly traded companies are valued at $778.6 billion, according to Bloomberg data. China sees Taiwan as part of its territory and has threatened to use force to prevent the island from declaring independence.

PetroChina surpassed the combined value of Exxon Mobil, Chevron and ConocoPhillips, the three largest U.S. oil producers. Their market capitalization totals $809 billion. Exxon Mobil was the world's biggest company by this measure, until Monday.

The Chinese company also has a higher value than Royal Dutch Shell, BP, Total and Eni, the largest oil companies based in Europe. The market cap of this quartet adds up to $847.6 billion.

PetroChina's first-day rally was also relatively steep, even for a Hong Kong company coming to the mainland this year. The stock's 163 percent advance was the third-biggest gain for those 10 debuts. Only China Oilfield Services and Aluminum Corp. of China, or Chalco, did better.

Yet even this showing failed to lift Chinese stocks. The CSI 300 index, which almost tripled earlier in the year, fell 2.1 percent after Prime Minister Wen Jiabao said his government might delay allowing mainland investors to buy Hong Kong shares.

The "through train," as the revisions have come to be known, may not be the whole story. PetroChina's start in Shanghai means the biggest mainland companies with Hong Kong listings have all come home. They can't pick up the market again.

History may be kinder to Stan O'Neal, Merrill Lynch's former chief executive officer, than to Chuck Prince, his ousted counterpart at Citigroup, because he came out far ahead in selecting a buyer for his firm's money-management business.

BlackRock's shares have climbed 31 percent since the company, based in New York, took control of Merrill Lynch Investment Managers in September 2006 in exchange for a 49 percent stake. Laurence Fink, the BlackRock chief executive, is a possible successor to O'Neal, and CNBC reported that he has been offered the job.

Citigroup also is considering Fink to succeed Prince, according to CNBC — and no wonder. The rally in BlackRock compares with a 38 percent decline in Legg Mason since that company swapped its broker network for Citigroup's fund unit in December 2005.

This year, Legg Mason, based in Baltimore, is doing worse than its flagship mutual fund, Bill Miller's Legg Mason Value Trust, which is lagging behind the Standard & Poor's 500 index for the second straight year after a 15-year winning streak. The stock has lost 20 percent, while the fund has fallen about 1 percent.