Stocks rebounded on Thursday -- the final trading day of the quarter -- after a volatile start to the week. All told, the Nasdaq Composite and the S&P 500 both popped about 1.5%, while the Dow Jones Industrial Average rose 1.1%.

But not every stock enjoyed today's outsize gains. Read on to learn why Acxiom Corporation (NASDAQ:ACXM)Longfin (NASDAQ:LFIN), and Starbucks (NASDAQ:SBUX) lagged the broader market today.

Facebook's third-party data crackdown

After plummeting nearly 34% early today, shares of Acxiom partially recovered to close down 19% as the marketing technology and services company announced that its relationship with Facebook (NASDAQ:FB) will soon come to an end. 

That's not to say the bad news was Acxiom's fault. Rather, Facebook announced that its Facebook Partner Categories product -- which leverages third-party data providers like Acxiom's Audience Solutions division -- will be discontinued over the next several months in response to its recent data-privacy controversy.

So while Acxiom doesn't expect any changes to its fiscal 2018 guidance, it warned that its revenue and profitability for fiscal 2019 will be reduced by as much as $25 million. 

That's a small slice of the $987 million in revenue that analysts were modeling for Acxiom next year. And the company still expects its LiveRamp segment will simultaneously grow by at least 30%. Nonetheless, it's hard to blame investors for taking a step back given this sudden loss of a meaningful revenue stream from a prominent customer.

Stock market prices in yellow with red and green arrows indicating direction on an LED display

Image source: Getty Images.

Longfin dives deeper

Longfin stock plummeted 48.8% today after the financial and cryptocurrency technology specialist was formally removed from the Russell 2000 Index less than two weeks after joining it. 

To be fair, the news shouldn't come as a complete surprise. Today's drop only adds to a more-than-50% plunge earlier this week -- a harrowing move that came after fraud accusations from a noted short-seller, and a later announcement from FTSE Russell that Longfin had failed to meet the minimum requirement for having 5% of its shares available to the public. Regarding the latter -- and this helps explain today's big drop -- Longfin stock stopped being included in the Russell 2000 index as of yesterday's market close.

I should also note that shares of Longfin had skyrocketed as much as 2,600% over the past few months after the company announced it had purchased blockchain microlending solutions company Ziddu.com. In doing so, Longfin effectively propelled itself into the spotlight as a cryptocurrency play for speculative traders. As such, with short-sellers still bearing down after its index removal, it's no surprise to see the stock plunging again today.

Did Starbucks' management overpromise on China?

Finally, shares of Starbucks fell as much as 2% early today -- a significant move for a business valued at over $81 billion -- before mostly recovering after an analyst warned that next year's sales growth may arrive below expectations.

According to Wedbush Securities' Nick Setyan, their recent analysis of the financial performance of Starbucks' China stores indicates that they will offer a "lower contribution to overall revenue growth than initial management commentary."

Setyan believes that Starbucks' China locations will "only" comprise around 20% of the company's overall growth next fiscal year. That's well below management's recent guidance for a contribution of around 25% from its fastest-growing geography.

Wedbush also lowered its rating on Starbucks stock to neutral from outperform, and reduced its per-share price target to $56 from $70.

That said, many appeared to shrug off these concerns today -- though the broader market's rise likely helped dull the impact of Wedbush's warning. But going forward, you can be sure investors will be closely watching Starbucks' progress in the Middle Kingdom.

Steve Symington has no position in any of the stocks mentioned. The Motley Fool owns shares of and recommends Facebook and Starbucks. The Motley Fool has a disclosure policy.