Amazon.com founder Jeff Bezos is one of the richest people in the world, worth $200 billion. Brother Mark Bezos could follow in the success of his older brother with a career in private investments. What Happened: Mark Bezosand David Moross recently launched HIPstr, an early-stage investment arm for their HighPost Capital private investment firm. HIPstr, raised $100 million and has invested in six companies, including one linked to Kylie Jenner. HIPstr is set to invest in what it calls early-stage consumer growth and consumer technology enablement companies. Bezos and Moross launched the new i…