American Capital, Ltd. was an American publicly traded private equity firm and global asset manager. American Capital, both directly and through its asset management business, originated, underwrote and managed investments in middle market private equity, leveraged finance and structured products. American Capital managed $10 billion of assets, including assets on its balance sheet and fee earning assets under management by affiliated managers. Founded in 1986 and publicly traded between 1997 and 2017, American Capital had six offices in the U.S. and Europe.

Through its private equity and leveraged finance business, American Capital participated in management and employee buyouts either by providing mezzanine and senior debt financing for buyouts led by private equity firms or by providing capital directly to companies through a 'One Stop Buyout' in which it funded senior debt, mezzanine and equity and was the controlling shareholder. American Capital and its affiliates invested from $10 million to $600 million per company in North America and €10 million to €300 million per company in Europe.

American Capital owned and managed European Capital, a fund with €0.9 billion of assets. European Capital invests in management and employee buyouts either by providing mezzanine and senior debt financing for buyouts led by private equity firms or by providing capital directly to companies through a 'One Stop Buyout' in which it funds senior debt, mezzanine and equity and is the controlling shareholder.

Since its 1997 IPO through to September 2015, American Capital had invested $37 billion in over 730 companies, including well-known companies such as AAMCO, Bumble Bee Seafoods, Bushnell Outdoor Products, Camelbak, Euro-Pro, Evenflo Company, Gibson Guitars, Piper Aircraft, Riddell and Rug Doctor.

Through its asset management business, American Capital managed publicly traded American Capital Senior Floating (NASDAQ: ACSF) and seven private funds.

American Capital had six offices in New York, Chicago, Annapolis, London, Paris with its home office in Bethesda, MD.

On January 3, 2017, American Capital completed its merger with Ares Capital Corporation.