Until recently, private equity seemed to have shed its bad-boy image of 20 years ago, summed up in "Barbarians at the Gate", a bestselling business book, a DVD and a film about the takeover battle by Kohlberg Kravis Roberts (KKR) to buy RJR Nabisco.
The old arguments and criticism have surfaced again. Some commentators have begun to write about the death of capitalism. Strangely, the threat has come, not from some radical far-left group, nor from a major ideological opposite such as Communism or Fascism, but from capitalism itself.
In a recently concluded meeting of the 36 countries of the European Union Trade Confederation (ETUC), European trade unionists proposed a global fightback to counter the rapidly growing role of private equity in taking over established companies.
The call came as the ETUC demanded that British ministers end the favourable tax treatment for private equity, introduce new disclosure rules and protect the conditions of workers in takeover targets.
According to the Financial Times, "With the volume of buy-out activity across the world running at $667bn (£334bn) last year, large chunks of the global corporate sector are becoming less transparent. In jurisdictions such as the US, where there is no requirement for private companies to make accounts publicly available, much information about business activity is disappearing into a black hole."
Critics of private equity takeovers argue that the new breed of very large, highly leveraged deals manipulate rules to avoid paying tax.
Equity privateers thus stand accused of wielding power without responsibility.
Private equity is facing a backlash from trade unions and politicians who have to protect workers rights and their lay-offs. Therefore, private equity firms are coming under increasing pressure to improve disclosure and come closer to listed public company reporting standards.
In today's complex financial markets, the central banks acting as watch dogs will find more difficult to determine the economic risks of the highly leveraged buy-outs.
Private equity firms buy struggling companies, fix them up, and sell them off, generating huge returns for their stakeholders. They do it away from public scrutiny.
The majority of investment into private equity funds comes from institutional investors.
The most prolific investors into private equity funds in 2006 were public pension funds and banks and financial institutions, which together provided 40% of all commitments made globally according to data from London-based Private Equity Intelligence Ltd.
Other prominent groups investing in private equity include corporate pension plans, insurance companies, endowments, family offices and foundations.
Capitalism will have turn on its head to get the private equity to become more transparent.