This week, which stocks lagged or dragged? Weekly Winners column keeps up with market trends, helping Tigers sort out the week's hottest sectors, stock winners and important news.

Below are top 10 S&P 500 stock gainers for the week ended Mar. 14:

WR Berkley Shares up 13% After MSI Announces Plans to Build 15% Stake

WR Berkley's shares have risen more than 10% in early trading following this morning's announcement that Japanese carrier Mitsui Sumitomo Insurance is to purchase 15% of its outstanding common stock.

All common stock will be purchased through open market or private block purchases, MSI said in a statement on Friday. It added that the Berkley family will not be selling any of its common stock, nor will MSI purchase common stock from WR Berkley.

MSI said its purchases of WR Berkley common stock from third parties will be made "over a reasonable time period". It added that it cannot acquire 10% or more of the outstanding common stock without certain regulatory approvals.

Dollar Tree Jumps 9% as It to Sell Family Dollar Business for $1 Billion

Dollar Tree is nearing a sale of its Family Dollar business to a consortium of private-equity investors for roughly $1 billion, according to people familiar with the matter. 

The discount-retail chain is set to be acquired by Brigade Capital Management and Macellum Capital Management, the people said. A deal is expected to be announced later Wednesday morning, when Dollar Tree reports its quarterly results, they added. 

The Wall Street Journal reported last summer that Dollar Tree, in the midst of a turnaround, had tapped bankers to conduct a strategic review of its Family Dollar division.

Though the two names sound familiar and are known for selling cut-rate merchandise, they serve different consumers. Dollar Tree stores are mostly in suburban locations and cater to middle-income households seeking party supplies, crafts or other knickknacks. (Dollar Tree historically sold most items at $1, though recently it has boosted some prices.) 

Universal Health Swinging to 'More Normal Cadence,' Morgan Stanley Says

Universal Health Services' business is swinging to a "more normal cadence" following a period of variability and distortions related to the COVID-19 pandemic, Morgan Stanley said in a note Wednesday.

Morgan Stanley said profitability in the company's behavioral segment has "rebounded sharply" and has marginally exceeded pre-pandemic levels. The behavioral health business accounts for 44% of Universal Health Services' revenue and 62% of its operating profit, according to the note.

"UHS is well positioned to address a growing gap in mental health care," Morgan Stanley said as it estimates that 23% of adults have mental health issues but only about half are being treated.

Cintas Surges 6% as Acquisitions Boost Workplace Uniform Supplier's Results

Shares of Cintas surged 6% this week as the provider of uniforms and other workplace products reported better-than-expected results and raised its profit guidance as it benefited from expansion.

The company posted third-quarter fiscal 2025 earnings per share (EPS) of $1.13, while analysts surveyed by Visible Alpha expected $1.06. Revenue rose more than 8% year-over-year to $2.61 billion, also above forecasts.

Cintas noted that revenue growth in the quarter "was positively impacted by 0.9% due to acquisitions," although it was negatively impacted by 0.4% because of foreign currency exchange rate fluctuations.

Tesla Stock Gains 6% After Trump Car Tariffs

President Donald Trump’s surprise tariff announcement on Wednesday evening is the reason car stocks face turmoil. Tesla stock, however, is getting a pass from investors thanks to its all-American manufacturing, even as CEO Elon Musk warns of higher costs.

The move came after Trump announced 25% import tariffs on all cars imported to the U.S. Key car parts are included, too. Trump’s prior plan contemplated import tariffs on Canada and Mexico. Those countries are still included, but European and Asian nations have been caught in Trump’s tariff net.

Tesla is in a relatively good position. It makes all the cars it sells in the U.S. in America. It does source parts from other countries, though, and those would be subject to tariffs, which Musk pointed out in a Wednesday tweet.