Stocks climbed on Monday, extending Friday's gains as U.S. treasury yields rebounded from historic lows and helped ease investors' concerns over an impending recession. Major indexes rallied, with the Dow and the S&P 500 gaining around 1% and 1.2%, respectively, but they still haven't fully recovered from their brutal sell-off early last week. 

However, the rising tide didn't lift all boats. Several individual stocks fell sharply, including Zscaler (ZS -14.10%), Palo Alto Networks (PANW -28.44%), and PG&E (PCG 0.90%).

A downgrade for Zscaler

Shares of Zscaler fell 11.3% after OTR Global downgraded the cloud-based cybersecurity specialist to "negative" from "mixed." To justify its relative bearishness, the analyst cited channel checks with Zscaler partners that showed concerns over increasing competition and discouraging sales trends. Regarding the latter, OTR elaborated that some Zscaler partners fell short of their sales goals in their most recent quarter, while others expect sales growth in the current quarter to lag that of the broader cybersecurity industry.

It certainly doesn't help that Zscaler stock had more than doubled so far in 2019 as of Friday's close, leaving it up more than 400% from its early 2018 IPO at $16 per share. Unless the company provides a preliminary update in the next few weeks, investors will need to wait until Zscaler's fiscal fourth-quarter 2019 earnings call early next month to see whether this downgrade was merited.

Stock market data with a red arrow chart indicating losses.

Image source: Getty Images.

Palo Alto Networks' latest executive turnover

Shares of Palo Alto Networks slumped as much as 3.6% before partially recovering to close down 0.6% after the company confirmed Executive VP of Worldwide Sales Dave Peranich is stepping down at the end of September. The stock had plunged more than 7% on Friday following early reports of the key executive departure. 

The move is the latest in a string of executive changes for Palo Alto Networks. Around this time last year, the company replaced CEO Mark McLaughlin -- who assumed the role of vice chairman of the board -- with former Google executive Nikesh Arora. Then last October it hired Google exec Amit Singh to replace former president Mark Anderson. And just last month, the company appointed marketing veteran Jean English as its new chief marketing officer.

It's not terribly unusual to see high-level executives depart as new CEOs settle in. But with Palo Alto Networks' next quarterly earnings call coming up early next month, investors are understandably concerned to see a key sales leader apparently jumping ship.

PG&E faces a big new risk

Finally, PG&E stock plummeted 25.3% following two new rulings from a U.S. bankruptcy court judge. First, the judge ruled the gas and electric utility will maintain the sole rights to propose its own bankruptcy reorganization plan -- a positive decision that effectively denied the requests of two investor groups to submit their own suggestions to that end.

But the judge also issued a separate ruling that says PG&E must face a jury trial allowing wildfire victims and insurance claimholders to challenge a California state agency's decision that PG&E was not responsible for the destructive wildfires that led the utility to file for bankruptcy in the first place. If those challenges are successful, PG&E could be on the hook for as much as $15 billion in additional damage claims.