Salesforce.com Inc.

Which business-software giant will become the go-to provider in a work-from-home world? Salesforce . com could put pressure on Microsoft Corp. , as it is in advanced talks to buy workplace messenger maker Slack Technologies Inc. Having failed to capture Slack itself, Microsoft in 2016 launched its own competing workplace collaboration tool, called Teams. Slack would be the largest acquisition ever for Salesforce ; Salesforce’s core business is in customer-relationship management software. Salesforce shares lost 5.4% Wednesday.

AstraZeneca PLC

Optimism that vaccines will help revive the economy in 2021 got another boost. On Monday the University of Oxford and AstraZeneca said their vaccine was found to be as much as 90% effective in preventing infections without serious side effects in a large trial. Unlike shots under development from Pfizer and Moderna, AstraZeneca’s vaccine can be stored at temperatures above zero degrees Celsius, easing the distribution process. U.S. stocks climbed Monday, with the Dow Jones Industrial Average rising 1.1%. American depositary shares of AstraZeneca shares fell 1.1%, as some investors appeared to be disappointed that its vaccine candidate’s effectiveness rates fell short of those reported by Pfizer and Moderna.

Delta Air Lines Inc.