The NYSE Group Inc. announced yesterday that it has closed its US$40 million agreement with the American Stock Exchange LLC for the NYSE to acquire the Amex’s one-third ownership stake in the Securities Industry Automation Corp.

The SIAC plans, develops, implements and manages a variety of automated information-handling and communications systems. These systems support order processing, trading, market data reporting, trade comparison and surveillance. The deal was announced on October 25.

The NYSE Group now wholly owns SIAC, including Sector Inc. and SFTI. Sector, a SIAC subsidiary, markets technological expertise and facilities to clients in the financial services and other industries. SFTI, SIAC’s Secure Financial Transaction Infrastructure, was developed to help the financial services industry substantially improve the resilience of telecommunications connectivity.

“NYSE Group is pleased to close this transaction with the American Stock Exchange,” said NYSE Group president and co-COO Jerry Putnam, who is also SIAC chairman and interim CEO. “For NYSE Group, full ownership of SIAC is consistent with our strategic business goals and greatly enhances our ability to serve our customers and investors worldwide.”