In fact, it’s only the second PE-backed IPO ever to raise more than $2 billion, following a $2.75 billion offering from Charter Communications (CHTR) in 1999. The rest of the top 5 all fall short: General Growth Properties ($1.99b), Google ($1.66b) and Neilsen ($1.64b).

But size alone isn’t why Kinder Morgan is so notable, particularly given that it likely will be dwarfed later this year by hospital operator HCA Inc., which has filed to raise more than $4 billion. Instead, the big story here is use of proceeds.

Most PE-backed IPOs are used for general corporate purposes, including acquisitions and retirement of debt. The private equity firms themselves sometimes sell part of their holdings, but the vast majority of shares are offered by the company itself. Just take a look at this analysis of the five largest PE-backed IPOs in 2005 and 2006, in which only one of the deals included significant sponsor liquidity. And, even in that case (Spirit Aerosystems), most of the shares still were offered by the company itself.

In the case of Kinder Morgan, however, all of the proceeds are going to company insiders. Here’s a breakdown:

• Goldman Sachs (GS): Sold 37.95 million shares ($1.14 billion in proceeds), and still holds 140 million shares (19.9% ownership stake)
• Highstar Capital: Sold 24 million shares ($720 million in proceeds), and still holds 140 million shares (19.9% ownership stake)
• The Carlyle Group: Sold 16.76 million shares ($502 million in proceeds), and still holds 88.87 million shares (12.6% ownership stake)
• Carlyle/Riverstone Funds: Sold 16.76 million shares ($502 million in proceeds), and still holds 62 million shares (8.8% ownership stake)
• Kinder Morgan (KMI) stock spiked above $32 per share in early trading, and has settled in at around $31.80 as of this writing. Goldman Sachs and Barclays Capital served as co-lead underwriters on the IPO.

That works out to around $2.86 billion in IPO proceeds, based on an original equity investment that Capital IQ  pegs at $4.5 billion. Kinder Morgan also reports that it paid out around $1 billion in dividends over the past two years, but does not specify the recipients. It’s likely some went to the sponsors, while some might have gone to management (including chairman and CEO Richard Kinder, who participated in the company take-private acquisition, did not sell any of his 216 million shares in the IPO).

The real question now is whether Kinder Morgan will serve as a trailblazer or as an outlier. There is a glut of large PE-backed companies just waiting to file for IPOs, and their sponsors must be looking at Kinder Morgan and wondering if they too can get a bunch of first-day liquidity.

Conventional wisdom is that the public markets want such issuers to use at least some proceeds to pay down debt. Harrah’s, for example, failed to price its IPO, in part, because all of its IPO proceeds were designated for expansion efforts.

Kinder Morgan has more than $12 billion in debt on its books, but its debt-to-EBITA ratio is only 3.6x — which comes in a bit below the typical ratio for a PE-backed IPO. In other words, public investors were comfortable with its level of debt. HCA, for example, had a debt-to-EBITA ratio of 4.5x at last check. Harrah’s was at a whopping 12.2x. [Update: Blackstone-backed semiconductor company Freescale today filed for a $1.15 billion IPO — most of the proceeds being used to pay down debt. Around a 6.6x debt-to-EBITDA ratio]

In other words, many PE-backed companies may be able to follow Kinder Morgan into the public markets, but they won’t be able to follow its lead.