BANGALORE - Tata Motors plans to acquire Japan's Sumitomo Corp's 53.5 percent stake in truck and bus maker Swaraj Mazda in a deal worth up to $54 million to boost its commercial vehicles business, the Economic Times reported on Thursday.

The deal value, if the plan succeeds, includes a mandatory 20 percent open offer to other shareholders, the newspaper said, citing a person close to the development.

It said private equity investors, CDC Group and Actis, which own 9.3 percent and 7.7 percent respectively in Swaraj, are likely to participate in the open offer if Tata Motors buy Sumitomo's stake. A Tata Motors spokesman told the paper the company would not comment on speculation. Officials at Sumitomo in Japan could not immediately be reached by Reuters. (Reporting by Sumeet Chatterjee; Editing by Ranjit Gangadharan)