Last week appeared calm from a broad perspective as major market indices remained nearly unchanged. A closer look reveals intense fluctuations featuring the year's largest single-day decline and rebound. This increased volatility encourages Ark Invest co-founder CEO and chief investment officer Cathie Wood to trade more actively.

Wood bought and sold stocks throughout the week. She boosted positions in Amazon.com (NASDAQ: AMZN) Roku (NASDAQ: ROKU) and Guardant Health (NASDAQ: GH) on Friday. Here is a closer review.

1. Amazon

The top online retailer led buying activity on Friday. Wood increased her Amazon stake across five of the six Ark Invest growth stock exchange-traded funds. The shares have dropped nearly 10 percent since releasing disappointing second-quarter results earlier this month.

Amazon improved over the last six trading days after the weak update. It revealed a partnership with TikTok late last week to help influencers on the short video platform earn income by promoting Amazon products. The deal lets TikTok users purchase featured Amazon items without exiting the app.

Image source: Getty Images.

Amazon's recent quarter fell short of expectations. Revenue grew a modest 10 percent missing forecasts while guidance for 8 percent to 11 percent growth offers little excitement. Earnings per share more than doubled and beat profit estimates yet the slowest top-line increase in over a year hurts a stock that reached record highs this summer.

Beyond e-commerce its Amazon Web Services cloud unit delivered 89 percent of operating profit last quarter providing strong margins. Acquiring shares at a nearly 10 percent discount from six days prior and 17 percent below the recent peak appeals to long-term Amazon supporters.

2. Roku

Roku trades lower after its monthly financial release yet the drop appears excessive. The streaming leader topped estimates across all metrics in its second-quarter report and raised guidance beyond analyst projections.

Platform usage keeps expanding with double-digit revenue growth for five straight quarters. Roku now serves 83.6 million streaming households up 14 percent from last year while streamed hours rose 20 percent showing engagement outpacing audience gains.

The company remains unprofitable on a reported basis but losses are shrinking and trailing free cash flow has reached nine figures. Its Roku Channel saw streaming hours jump 75 percent year over year.

3. Guardant Health

Guardant Health shares fell 4 percent on Friday marking the weakest performance among these three purchases. No negative news emerged as the oncology test developer delivered strong results earlier in the week exceeding revenue and earnings targets while raising full-year guidance.

Guardant offers few current products for clinical or biopharma use but its pipeline strengthens with Shield a colorectal cancer screening tool nearing FDA approval. This would complement the Guardant360 suite of liquid and tissue oncology tests boosting expansion prospects.

Guardant anticipates profitability only in 2028 yet long-term holders may benefit as revenue is projected to triple to 2 billion dollars by then. Strong growth narratives often require extended timelines.

Should you invest 1000 dollars in Amazon right now?

Before purchasing Amazon shares review this:

The Motley Fool Stock Advisor team recently selected what they view as the 10 best stocks for investors to buy now and Amazon did not make the list. The 10 chosen stocks may deliver substantial gains ahead.

Consider that Nvidia appeared on this list on April 15 2005 and a 1000 dollar investment then would now equal 641864 dollars.

Stock Advisor offers a clear success plan with portfolio guidance regular analyst updates and two fresh stock picks monthly. The service has more than quadrupled S and P 500 returns since 2002.

See the 10 stocks.

Stock Advisor returns as of August 12 2024.

John Mackey former CEO of Whole Foods Market an Amazon subsidiary serves on The Motley Fool board. Rick Munarriz holds Roku shares. The Motley Fool maintains positions in and recommends Amazon Guardant Health and Roku. The Motley Fool follows a disclosure policy.

The views and opinions expressed herein are the views and opinions of the author and do not necessarily reflect those of Nasdaq Inc.