The Chicago Stock Exchange has cleared a major hurdle as it attempts to sell itself to a Chinese-led investment group.

The Committee on Foreign Investment in the US, known as CFIUS, on Wednesday approved the exchange's proposed sale to Chongqing Casin Enterprise Group Co and others, said Drew Mauck, a spokesman for the Chicago Stock Exchange. Signed in February, the deal is still subject to approval by the US Securities and Exchange Commission.

The Chicago Stock Exchange is attempting the sale at a potentially fraught time for business relationships between the US and China. CFIUS scrutinizes purchases of US companies by foreign buyers to identify national security issues, and there was no guarantee that it would approve the proposed sale.

Earlier this month a China-based group's attempted takeover of German semiconductor-equipment supplier Aixtron SE crumbled as US President Barack Obama moved to block the deal on the grounds of national security risk.

A subsidiary of CHX Holdings Inc, the Chicago Stock Exchange is the second-smallest stock exchange in the US, handling less than 0.5 percent of equity volume. Even so, the exchange would provide a foothold in the $25 trillion market for US equities, and could become a place for Chinese companies to list.

The takeover bid was valued as less than $100 million, Bloomberg News reported when an agreement was signed. If the sale succeeds, it would be the first time a Chinese company purchased a US exchange operator.

Bloomberg