When Tamao Sasada was put in charge of a large Japanese corporate client, she broke into a cold sweat. Now, the Bank of America Corp. executive is urging other female colleagues to take on new challenges as she forges a path in sustainable finance.

Then a Merrill Lynch employee in her 30s, she wasn’t aware of any other women investment bankers who had been given such a big assignment in the country’s male-dominated business world.

"Honestly speaking, I had some uneasiness,” Sasada, Bank of America’s country head for Japan, said in a recent interview. She recalls that she would often be the only woman in meetings with clients. "But after handling that work, I really felt glad that I did it — the key is ‘just give it a try.’”