Ark Invest is a big company that buys and sells stocks of other companies. They decided to sell some shares of a company called Nvidia, which makes computer chips. This happened even though the price of those shares went up a little bit. But they also bought more shares of another company called Roku, which makes TV streaming devices. People are worried that if Nvidia's stock price goes down too much, it could affect other companies and the whole market. But Nvidia is still doing well and making money from its business. Read from source...

1. The article title is misleading and sensationalized, implying that Ark Invest dumped Nvidia shares due to a rebound in Roku, while the actual reason was a diversification strategy within their ETFs.
2. The article does not provide any context or background information on why Ark Invest chose to sell Nvidia shares or buy Roku shares, which leaves the reader uninformed and confused about the rationale behind these trades.
3. The article focuses too much on the market cap loss of Nvidia and the rebound of its shares, rather than the performance and prospects of both companies in their respective industries.
4. The article mentions concerns about Nvidia's influence on the S&P 500 Index, but does not provide any evidence or analysis to support this claim, making it a mere speculation without factual basis.
5. The article cites Jim Cramer as an authority figure, but does not disclose his affiliation with CNBC, which could create a potential conflict of interest and bias in his opinions on these stocks.

1. Arcturus Therapeutics (NASDAQ:ARCT) - ARK Innovation ETF (ARCA:ARKK): Buy, high growth potential, gene therapy and mRNA-based drugs, risk of regulatory hurdles and competition from other biotech companies.
2. Roku Inc (NASDAQ:ROKU) - ARK Innovation ETF (ARCA:ARKK): Buy, dominant position in the streaming market, strong growth in subscribers and revenue, risk of changing consumer preferences and regulatory scrutiny.