What Is Private Equity?
Private equity is an investment strategy where firms raise pools of capital from institutional investors and use that money to buy controlling stakes in companies that are not traded on public stock exchanges. Unlike public market investors who buy small pieces of many companies, private equity firms typically acquire entire businesses, hold them for roughly three to seven years, and then sell them through a sale to another buyer or an initial public offering.
The industry is built around the fund structure: a private equity firm acts as the general partner (GP) that manages the fund, while pension funds, endowments, sovereign wealth funds, and wealthy individuals invest as limited partners (LPs). The GP earns a management fee on committed capital plus a share of the profits called carried interest, most commonly under the 2-and-20 model.
How a Private Equity Deal Works
The classic private equity transaction is the leveraged buyout, or LBO. The firm buys a company using a relatively small slice of equity from its fund and a large amount of borrowed money, often 50% to 70% of the purchase price. The debt sits on the acquired company's balance sheet and is paid down with the company's own cash flows over the holding period.
Because the equity check is small relative to the total purchase price, any growth in the company's value accrues disproportionately to the equity holders. During ownership, the firm works to grow revenue, expand margins, make add-on acquisitions, and pay down debt, all of which increase the equity value at exit. Returns are measured primarily with internal rate of return (IRR) and multiple on invested capital (MOIC).
Example
Suppose a PE firm buys a company for $1 billion using $400 million of equity and $600 million of debt. Over five years, the company grows EBITDA, pays down $300 million of debt, and is sold for $1.4 billion. The remaining debt of $300 million is repaid at exit, leaving $1.1 billion for the equity holders.
That turns $400 million of equity into $1.1 billion, a 2.75x multiple on invested capital and roughly a 22% IRR over five years. This mechanical walk from purchase price to equity proceeds is exactly what interviewers test in a paper LBO, one of the most common private equity interview exercises.
Why It Matters
Private equity is one of the largest destinations for investment banking analysts after their two-year programs, and firms like Blackstone, KKR, and Apollo manage hundreds of billions of dollars each. Understanding how leverage amplifies equity returns, how funds are structured, and how GPs get paid is foundational for anyone pursuing a buy-side career.
For companies, private equity ownership brings capital, operational discipline, and pressure to perform, though critics point to the heavy debt loads placed on portfolio companies. Either way, PE now touches a huge share of the economy, from software businesses to hospitals to retail chains.
