Less than a year after it raised a $15 million Series B, Public, a social-focused free stock trading service, has raised a $65 million Series C. The startup is not the only company to raise successive rounds this year. Welcome has managed the feat, along with Skyflow and others. Public’s Series C, therefore, fits into the trend of investors doubling down into startups that they think have potential. After an initial freeze during the early pandemic months, venture capitalists and other investors accelerated the pace at which they deploy late-stage…