New York’s top banking regulator has asked Symphony Communication Services, an instant messaging software company soon to be used by some of the world’s biggest banks, for details about its document retention capabilities and other features.

In a letter sent to the company Wednesday, the Department of Financial Services asked Symphony for details about data retention and deletion, encryption services and open-source features. A handful of banks regulated by the DFS- Bank of New York Mellon, Credit Suisse, Deutsche Bank and Goldman Sachs-have invested in the company's technology, according to the letter.