Indian companies invested $1.29 billion in overseas units and joint ventures in September, according to RBI data.
Companies had invested $1.94 billion overseas in August.
Alok Industries, Simplex Infrastructures, Tata Petrodyne, Cadila Healthcare, Piramal Enterprises, Mercator and Bharti Airtel were among the major investors last month.
Alok Industries invested $165.22 million in two tranches in wholly owned units in the United Arab Emirates and the US. The companies are into wholesale and retail trade, restaurants, hotels and manufacturing businesses.
Simplex Infrastructures invested $75 million in its construction joint venture in Oman and Tata Petrodyne made an investment of $69 million in its wholly owned business in the Netherlands, which is engaged in agriculture and mining.
Cadila Health Care invested $55.64 million in its wholly owned company in Ireland. Tata Power invested $ 36.89 million in two separate wholly owned units based in Mauritius and Singapore.
Piramal Enterprises made an investment of $48.41 million in a wholly owned unit in Switzerland and a joint venture in the US.
Mercator invested $40.75 million in a wholly owned company in Singapore while telecom major Bharti Airtel invested $38.5 million in a wholly owned company in Mauritius.