Private equity exits exceeding $20 billion are relatively uncommon and often reshape entire industries. These transactions typically reflect years of operational improvement, balance-sheet optimisation, and aggressive sector consolidation carried out under private equity ownership. The following three deals, Calpine, Worldpay, and Alliance Boots, illustrate how PE sponsors generated significant value across the energy, payments, and healthcare retail sectors before exiting to strategic acquirers seeking greater scale, operational synergies, and market leadership.
6. Alliance Boots ($22 billion)
Seller: KKR & Co. Inc. Buyer: Walgreens Boots Alliance
KKR’s $22 billion sale of Alliance Boots to Walgreens stands as one of the most successful investments in healthcare retail history. Originally acquired in 2007, Alliance Boots was Europe’s leading pharmacy and health-and-beauty retailer, operating approximately 3,300 stores across 20 countries.
Under KKR’s ownership, alongside executive chairman Stefano Pessina, the company underwent significant operational improvements, including supply-chain optimisation, international expansion, and growth into emerging markets. Walgreens initially acquired a 45% stake in 2012 before completing the full takeover in 2014.
The strategic logic behind the transaction was compelling. Walgreens sought to establish a global pharmacy and healthcare leader with integrated retail and wholesale capabilities, while the combined business gained substantial purchasing power, broader international reach, and stronger global brand recognition. For KKR, the exit generated one of the firm’s largest realised investment gains, reinforcing the effectiveness of long-term, operationally focused private equity ownership. More broadly, Alliance Boots demonstrated how private equity can transform a strong regional company into a globally strategic asset attractive to multinational acquirers.
5. Worldpay ($24 billion)
Seller: GTCR LLC Buyer: Global Payments Inc.
Worldpay’s $24 billion sale to Global Payments in 2019 marked a defining moment in the consolidation of the fintech industry. Prior to the transaction, GTCR and Advent International had combined Worldpay with Vantiv to create one of the world’s largest payment processing platforms, serving merchants across 146 countries.
During private equity ownership, Worldpay significantly expanded its technology capabilities, strengthened its omnichannel payment solutions, and built a highly recurring revenue model driven by transaction-based fees. The sponsors also benefited from major structural trends, including the rapid growth of e-commerce, digital wallets, and contactless payments, positioning the company as a global leader in digital payments infrastructure.
The strategic rationale for the acquisition was clear. Global Payments sought greater international scale and broader processing capabilities to compete more effectively with major industry players such as Fiserv and PayPal. The merger created a payments powerhouse handling more than 50 billion transactions annually and demonstrated how private equity-backed fintech businesses can evolve into critical infrastructure providers for global commerce. More broadly, Worldpay’s exit reflected the classic private equity strategy within technology-enabled financial services: scale through acquisitions, modernise platforms, and ultimately exit through strategic industry consolidation.
4. Calpine ($27 billion)
Sellers: CPP Investments | Investissements RPC, Bridgepoint Group Buyer: Constellation Energy
Calpine’s $27 billion sale to Constellation Energy stands among the largest private equity exits ever completed in the energy sector. The company was originally taken private in 2018 by a consortium led by CPP Investments and Energy Capital Partners. At the time, Calpine was one of the largest independent power producers in the United States, operating natural gas and geothermal facilities with total generation capacity exceeding 26 GW.
During private equity ownership, Calpine prioritised operational improvements, balance-sheet optimisation, and strategic positioning for the broader energy transition. Significant investment was directed toward flexible generation assets capable of stabilising power grids increasingly reliant on intermittent renewable energy sources. By the time of the transaction, Calpine had evolved into a strategically important component of North America’s lower-carbon energy infrastructure.
For Constellation Energy, the acquisition provided an opportunity to broaden its clean-energy portfolio while integrating Calpine’s dispatchable generation capabilities. The combined company emerged as one of the most diversified independent power producers in the United States, strengthening its ability to manage renewable volatility and meet rising electricity demand. More broadly, the deal reflected growing strategic interest in flexible baseload power assets and demonstrated how private equity firms can reposition traditional energy businesses into future-oriented platforms aligned with decarbonisation trends.