Asset management company the TCW Group has acquired Los Angeles private equity firm Craton Equity Partners.

Craton invests in companies that it deems socially responsible. The firm was found in 2006 and provides private equity capital to venture-backed companies in the sustainability, resource efficiency and carbon-reducing technology sectors. The firm has $241.5 million in assets under management. Craton’s investments include Sungevity, RecycleBank and Gazelle. Terms of the transaction were not disclosed.

“The acquisition of Craton Equity further expands our alternative asset management platform at a time when institutional investors are increasingly issuing mandates for socially responsible investing,” says Jess Ravich, managing director at TCW.

Craton managing partners Bob MacDonald and Tom Soto will become managing directors at TCW.

TCW, founded in 1971, develops and manages investment products that aim to enhance clients’ wealth. The Los Angeles firm has more than $130 billion in assets under management. The company’s clients include corporate and public pension plans, financial institutions, endowments and foundations and high-net worth individuals.

For more on socially-responsible investing, see “Private Equity: Investing ‘Responsibly?’”