Leading private-equity firms Carlyle Group, Texas Pacific Group and Kohlberg Kravis Roberts & Co. have received an unexpected offer from investment bankers from Morgan Stanley and Goldman Sachs Group Inc. that propose to take them public.

Private-equity business has always been about the acquisition of a major or controlling stakes in private companies or in divisions of public companies using the financial resources of a few affluent families. The breakthrough IPO of RHJ International, a company created by Ripplewood Holdings, on a Belgian stock exchange in March could start a new era in the business of private equity. This change would facilitate the raising of the funds replacing the roadshows that seek financing for the funds with a life of five to 10 years and supply the permanent capital to the firms.

Carlyle and Blackstone are regarded as the most likely candidates to re-shape their profiles going public, as Blackstone is closer to a conventional Wall Street investment banking entity, and Carlyle runs a variety of funds that can help it to smooth earnings, likely to be erratic at private-equity firms.

The issue of an IPO would raise questions as to whether investors might enjoy the bumpy rides earnings at such companies often experience. If earlier the earnings of the companies allowed investors to earn five times the amount invested, the companies could also worry less about their failures as they did not have to make quarterly reports public. The discussions of the IPOs also prompt that the heyday of private equity may be over.