Nikkei rises

Japan's benchmark stock index Nikkei advanced on Wednesday, as heavyweight SoftBank Group Corp soared after a US federal judge approved a merger between its US wireless unit Sprint Corp and T-Mobile US Inc.

The Nikkei share average closed 0.74% higher at 23,861.21, while the broader Topix slipped 0.04% to 1,718.92.

SoftBank Group jumped 11.9% to become the country's second-biggest company by market value after a US federal judge rejected an antitrust challenge to the proposed takeover of SoftBank's subsidiary Sprint by T-Mobile.

The tech conglomerate's stock has risen 20% year-to-date, especially after US activist Elliott Management amassed a stake of almost $3 billion and pushes for change at the firm, including $20 billion in stock buybacks. Under pressure to boost shareholder value, SoftBank is likely to launch a share buyback this month, Jefferies analyst Atul Goyal wrote in a note.

SoftBank was the most-traded stock on the main board and the jump in the stock lifted the information and communication sector sub-index 2.3%, making it the best-performing sector on the Tokyo bourse.