Exxon Mobil Corp. (NYSE: XOM) has long held the title of the world's largest oil company, but some analysts are starting to question whether it will be able to keep its crown, as the Chinese oil company PetroChina Corp. (NYSE: PTR) is quickly closing the gap.

As it stands now, Exxon Mobil still holds the No. 1 slot with a market capitalization of $506 billion. With a little over $443 billion market capitalization, PetroChina is the world's second-largest company, having recently surpassed General Electric (NYSE: GE). This gap is definitely going to shrink early next month when PetroChina debuts on the Shanghai Stock Exchange.

PetroChina announced last night that it expects to raise around $8.9 billion when it begins trading on the Shanghai exchange on November 5. Many analysts think that this number is way too conservative, but even at this level this would make the PTR debut the largest IPO of the world, and bring the company within striking range of Exxon Mobil's top position.

Some analysts are already predicting that the new shares will rise enough on opening day to push PetroChina ahead of Exxon Mobil in market capitalization. Earlier this week Chinese brokerage Ping An Securities stated in a report to investors that it expects PetroChina's new shares to trade up to 39.50-43.45 yuan on listing day. This would be enough to give PTR the title of the world's largest company.

Michael Fowlkes has worked as a stock trader for seven years and spent the last two years working as an analyst for the online investment advisory service Investor's Observer

Today marks the first time that Google (NASDAQ: GOOG) has touched upon the magical market capitalization figure of $200 billion. This is the company that will be the centerpiece of every MBA class 20 years from now, if not sooner. We have never seen anything like this before in the annals of the American stock market, nor anywhere else in the world. The stunning achievements of this 9-year-old company pale in comparison to where it is going to be in 3 years, 5 years and 10 years. Yes, the stock is still a buy -- actually a strong buy.

Traditional analysts and investors have attempted to put traditional barriers on Google when analyzing it. Can't do that, not going to work. Why? Because the world in which Google competes and dominates is so evergreen, that trying to put traditional growth numbers to the industry is nearly impossible. Google doesn't sell a physical hard product that requires delivery, set-up and training (although a Google phone is on the horizon). It operates in a virtual world -- and that's why many analysts and investors have tried to "temper" expectations. Temper is a fancy word for they haven't understood the story, have missed the story, and this is why it could become the first trillion dollar market-cap company.

In its much-watched New York Stock Exchange debut Friday, private equity firm The Blackstone Group LP (NYSE: BX) closed at $35.06 on volume of 113.1 million shares, up 13.10% from its initial-public-offering price of $31. Blackstone's shares did however finish $1.39 lower than Friday's opening price of $36.45 after spending most of Friday's session stalled between $35 and $36.

Blackstone raised $4.13 billion Thursday in its 133.4-million-share IPO, the largest in the U.S. since CIT Group Inc. (NYSE: CIT)'s $4.6 billion IPO in 2002. The shares outstanding represent a 12.3 percent stake in the buyout firm; Friday's $4.06-per-share gains bring Blackstone's capitalized value from $33.5 billion to just under $38 billion -- not too shabby.

More Blackstone coverage on BloggingStocks

• Tom Taulli: Blackstone sixth among IPOs
• Tom Taulli: Expert on Blackstone IPO
• Peter Cohan: Napoleon-watch: Blackstone's disappointing debut
• Joseph Lazzaro: Is the Blackstone IPO right for you?
• Sarah Gilbert: Blackstone Group IPO: Do you want in?
• Peter Cohan: Blackstone IPO not a great deal for bankers or public
• Georges Yared: Blackstone Group: Going public because it can
• Tom Taulli: Blackstone IPO: Looking for the greater fool