Shares of Kinder Morgan Inc rose more than 5 percent above their initial public offering price on Friday as investors scooped up stakes in the U.S. pipeline company.

The shares were up 5.2 percent to $31.57 in afternoon trading on the New York Stock Exchange after the company had the largest U.S. energy IPO since 1998, according to Thomson Reuters data.

Houston-based Kinder Morgan raised $2.86 billion on Thursday in an IPO valuing the firm at more than $21 billion.

It's a high-quality company that still has pretty decent growth, said Nick Einhorn, research analyst at Renaissance Capital.

Backed by private equity investors including Carlyle Group and Goldman Sachs Group Inc's buyout fund, Kinder Morgan upsized its IPO as shareholders sold a 13.5 percent stake in the company.

The IPO was seen as a means for Kinder's private equity partners to monetize their investment and an opportunity for investors to gain access to the company's track record of steady cash flows and its vast network of pipelines spanning the United States and stretching for 2,500 miles in Canada.

It's a blue-chip from day one, said Francis Gaskins, president of It's a blue-chip that institutions have no problem owning.

Historically, institutional investors have shunned buying into partnerships because of tax complications, but this offering was a way for them to add pipeline and storage assets to their portfolios.

Kinder Morgan's offering represented interest in its master limited partnership (MLP), Kinder Morgan Energy Partners LP . MLPs are favored by owners of cash-generating pipeline and other energy infrastructure assets because of the low tax liability, which provides MLPs with a lower cost of capital.

A lot of appeal of this is related to the company's assets that generate stable recurring cash flows, said Morningstar energy analyst Jason Stevens.

The underlying MLP has forecast an increase of about 4.5 percent in its dividend yield this year, which would mean an even bigger yield growth for Kinder Morgan Inc investors, Einhorn said.

The IPO price of $30 per share implied a yield of 3.9 percent based on $1.16 per share in dividends the company said it would pay annually if it was public for all of 2011, Einhorn said.

Even though all shares in the offering were sold by existing shareholders, Kinder Morgan's private equity investors and management will retain control of nearly 90 percent of the company. Chief Executive Officer Rich Kinder, who led the 2007 buyout of the company, is keeping his entire 30.6 percent stake.

The CEO previously was president of energy company Enron Corp but left in 1996 -- years before it became caught up in an accounting scandal and went bankrupt.

In the United States, Kinder Morgan owns 15,000 miles of natural gas pipelines and 8,400 miles of refined petroleum product pipelines running gasoline, diesel fuel, jet fuel and natural gas liquids. It also has 120 fuel terminals, gas storage facilities, carbon dioxide pipelines and stakes in eight West Texas oil fields.

Pipeline investments could increase as power plants begin burning more natural gas instead of coal, as new shale gas sources are developed, or even to feed the need for facilities to export U.S. gas at cheaper prices.

Pricier crude could also lead to a greater need for more oil storage, as well as pipeline capacity for the output of quickly expanding projects in the Canadian oil sands.

Kinder Morgan is the biggest U.S. energy IPO since Conoco Inc's $4.4 billion offering more than a decade ago.

The company sold 95.5 million shares for $30 each in Thursday's IPO. It originally planned to sell 80 million shares at $26 to $29 each.

The upsizing followed an above-range IPO pricing by another private equity-backed company, Nielsen Holdings , and is a good sign for private equity firms looking to begin the process of selling portfolio companies bought during the height of the buyout boom of 2005 to 2007.

They will be judged on their own merits, but certainly a fact that there's been two large successful private equity-backed IPOs is a positive for other companies looking to go public, Einhorn said.

Hospital operator HCA, which hopes to raise up to $4.6 billion, and retailer Toys R Us , which hopes to raise up to $800 million, are also expected to go public in the United States this year.

Underwriters on the Kinder Morgan offering were led by Goldman Sachs and Barclays Capital.

(Additional reporting by Braden Reddall in San Francisco; editing by Gerald E. McCormick, Phil Berlowitz, John Wallace)