Last week was pretty ho-hum if you zoom out. The major market averages were essentially flat. Zoom in, and you get wild volatility. Last week contained the largest single-day drop -- and single-day rise -- of the year. This is the kind of uptick in volatility that makes Ark Invest co-founder, CEO, and chief investment officer Cathie Wood more pecking than usual.

Wood was actively buying and selling stocks last week. She added to her existing positions in Amazon.com (NASDAQ: AMZN), (NASDAQ: ROKU), and Guardant Health (NASDAQ: GH) on Friday. Let's take a closer look.

The leading online retailer was the belle of the buying ball on Friday. Wood raised her stake in Amazon in five of the six Ark Invest growth stock exchange-traded funds (ETFs). The stock has fallen nearly 10% since posting disappointing second-quarter results earlier this month.

Continue reading

Source Fool.com