Stocks advanced strongly Monday, with both the Dow Jones Industrial Average (DJINDICES:^DJI) and the S&P 500 (SNPINDEX:^GSPC) setting record highs.

Today's stock market

Index Percentage Change Point Change
Dow 0.68% 144.71
S&P 500 0.83% 20.31

Data source: Yahoo! Finance.

Technology shares rebounded strongly from recent weakness and led the market higher, with the Technology Select Sector SPDR ETF (NYSEMKT:XLK) up 1.5%. Biotech stocks had their best day in months, and the SPDR S&P Biotech ETF (NYSEMKT:XBI) gained 3.6%.

As for individual sticks, trading began in the company formerly known as Yahoo!, and shares of PerkinElmer (NYSE:PKI) rose on news of a major acquisition.

Upward-moving stock chart superimposed on world map

Image source: Getty Images.

What's left of Yahoo! starts trading

Verizon Communications closed its acquisition of the core of Yahoo!'s business last week, and the part that remained changed its name to Altaba (NASDAQ:AABA) and started trading today. Altaba registered as a publicly traded, non-diversified, closed-end management investment company. The closed-end fund owns a 15% equity stake in Alibaba Group Holding Limited, a 36% equity stake in Yahoo Japan, and other investments, including a portfolio of patents that weren't important to Verizon. Shares of the company closed up 3.6% on their first day of trading.

Observers have long considered these equity investments to be undervalued while they were part of Yahoo!, so part of the motivation for spinning them off into a publicly traded fund was to unlock value. As of last Friday, the shares were priced at a 29% discount to the value of the assets, according to a letter issued today by the Altaba CEO Thomas J. McInerney, and today's market response didn't do much to change that. The market is discounting the shares in order to account for the tax liability that would be realized should the assets be sold, but management believes it can take some actions to reduce the discount. McInerney wrote:

Going forward, we expect cash to be repatriated, our asset list to shorten, and liabilities and contingencies to be resolved. Continuing to reduce complexity and contingencies feels inevitable and, while there are no guarantees, we believe that simplification will support a reduced discount.

Investors apparently want to see more specifics before shelling out for the stock.

PerkinElmer makes an acquisition

Medical instrument maker PerkinElmer announced the acquisition of EUROIMMUN Medical Laboratory Diagnostics AG today, and investors applauded, sending the shares up 6.5%. PerkinElmer is purchasing the German diagnostic instrument maker for $1.3 billion in cash. 

Euroimmun complements PerkinElmer's diagnostic offerings, adding products for auto-immune, infectious disease, and allergy testing. It is expected to deliver $310 million in sales this year, 95% from outside the Americas, and has averaged revenue growth of 19% over the last five years. Robert Friel, chairman and CEO of PerkinElmer, said in the press release, "With the acquisition of EUROIMMUN and its talented team of professionals, we are able to leverage our combined advanced detection, imaging and assay development capabilities, along with our strong collective market positions and synergistic commercial activities, to deliver better and more complete solutions to our customers around the world."

Investors have appreciated PerkinElmer's steady performance of late, bidding up the stock 30% since the beginning of the year. The Euroimmun purchase extends its reach in important growth areas of the market and also plays into the company's strategy of growing its business in China, where Euroimmun generates 45% of its sales. Investors also no doubt like the $0.28 to $0.30 the deal should add to non-GAAP 2018 earnings per share, which was $2.60 in 2016.