SAN FRANCISCO — For Rick Heitzmann, a venture capitalist at FirstMark Capital, the moment is now.

Two companies that FirstMark invested in years ago, Pinterest and Postmates, have filed paperwork to go public. Pinterest unveiled an offering prospectus on Friday. A third company, Airbnb, is expected to do the same within the next year. All are likely to be embraced by Wall Street, generating huge profits for FirstMark.

Which means it’s time for Mr. Heitzmann, whose New York investment firm has kept a relatively low profile, to consider hiring a public relations agency.

The flood of initial public offerings is an occasion for FirstMark to “tell our story,” he said. “We have been part of some of the more successful start-ups in the last several years and have been instrumental to their growth, often as the first investor. That’s a good story to tell.”

Across tech land, investors who helped nurture “unicorns,” the start-ups valued at more than $1 billion, are now getting ready to embody a different animal metaphor: the peacock.