HANOI, March 18 (Reuters) - Vingroup has sold 41.5% of its stake in its retail unit, Vincom Retail, to an undisclosed partner for an undisclosed sum, according to the company's filing to authorities.

After the transaction, Vincom Retail is no longer a Vingroup unit, the filing said. The stake was worth almost $1 billion on Monday, according to LSEG data. (Reporting by Phuong Nguyen and Yantoultra Ngui)