Citadel Securities Buys Morgan Stanley’s Options Market Maker

Citadel Securities bought Morgan Stanley’s unit focused on electronic market-making for US equity options, expanding the firm’s already dominant role in the popular derivatives, according to people familiar with the matter.

The trading firm founded by billionaire Ken Griffin acquired Morgan Stanley’s on-exchange options business and took on a large portfolio of equity options positions, the people said. The deal includes specialist posts on venues including Cboe, Nasdaq, NYSE and MIAX, the people said, asking not to be identified discussing private information.

The total purchase price couldn’t be immediately learned. Representatives for Miami-based Citadel Securities and New York-based Morgan ...