Facebook's (FB - Get Report)  latest challenge policing disturbing content has reignited broader concerns about the company. 

Specifically, more executive departures are high atop the list of issues investors have their eyes on. Facebook product chief Chris Cox announced his departure from the company last week, as well as What'sApp head Chris Daniels.

"Silicon Valley is a competitive place for top talent and losing these senior executives from FB may cause them to land at a company that competes with FB," wrote Needham and Co. analyst Laura Martin, who downgraded Facebook from Buy to Hold, in a note out Monday morning. 

Facebook shares were down 3.32% to $160.47 a share Monday. 

More departures could follow, Martin believes, especially as issues like the recent live streaming of the mass shooting at a mosque in New Zealand and Facebook's inability to quickly and fully take down videos of it, come up.

"Horrific images uploaded to FB (like the recent New Zealand events) that are technologically difficult to block at the 100% level and which hurt FB's brand" are at the top of Martin's list of concerns for Facebook. "Together, we believe these risks are causing a Negative Network Effect, as evidenced by senior management departures," she said. 

The Network Effect in Facebook's case, Martin says, plays out when each additional employee who has a particular belief contributes to other's adopting the same belief. Martin noted that Cox and Daniels may very well have left the company because they don't agree with broader strategy, so "other people in the organization will agree with them and leave also." 

Despite the downgrade, Martin left her price target unchanged at $169 , roughly 4% above the stock's current level. 

Shares could be pressured by negative sentiment, a theme that haunted the stock in 2018, and Martin, who is keeping her 2019 earnings per share estimate at $7.38, has grown less confident in the upside, with regulation remaining a risk.

BMO Capital Markets analyst Daniel Salmon wrote in a note out Friday Netflix (NFLX - Get Report) is a better pick than Amazon (AMZN - Get Report) in his mind, as it faces less regulation risk, a key factor Wall Street is considering when picking big tech stocks. 

Facebook shares are up 24% this year. 

Amazon and Facebook are holdings in Jim Cramer's Action Alerts PLUS Charitable Trust Portfolio. Want to be alerted before Cramer buys or sells AAPL or GOOGL? Learn more now.

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