These stocks could help you build a millionaire-maker portfolio.Cathie Wood is known for her focus on disruptive technology. Her company, Ark Invest, invests in high-growth tech stocks for its exchange-traded funds (ETF), each of which has a specific focus.Not surprisingly, Ark's stocks tend to do better in bull markets but often come with a lot of risk. In general, buying an ETF gives you exposure to a group of stocks and reduces your overall risk. But when most of the stocks are risky, that isn't necessar ...