New Delhi, Aug. 24 -- A group of 70 investors has come together to complain of shortcomings in how HDFC Bank, India's biggest private lender by assets, sold them a high-yielding financial product, marking the second such instance of customer complaints against the bank in West Asia.

According to the members of the group, who say they account for $12.5 million (nearly Rs.120 crore) of an estimated $100 million that HDFC Bank raised from customers, the investment was pitched as a unique investment opportunity between 2017 and 2019, promising returns of 14-16%.

One of the investors, Umesh Kumar Chandanani, a retired banker in Australia, said he received a call from his HDFC Bank relationship manager sometime in 2019 pitching the said retur...