AllianceBernstein's (AB) preliminary assets under management rose to $905 billion at the end of June from $899 billion in May, the company said Monday.

The "increase was primarily driven by firmwide net inflows, including a large low-fee passive fixed income mandate, as markets had a largely neutral impact on AUM during the month," the company said.

The asset manager said June net flows were "positive across all three distribution channels" led by its retail business, and followed by its institutions and private wealth segments.

For the quarter ended June 30, preliminary firmwide net inflows were $700 million, the company said.