Altair Engineering’s $10 billion-plus deal to be acquired by Siemens is the biggest deal by dollar value since Dupont’s merger with Midland-based Dow Chemical Co. (That "merger of equals" stock swap valued each company at about $65 billion.)

Learn more about whether Altair Engineering Inc. or Nebius Group N.V. is a better investment based on AAII's A+ Investor grades, which compare both companies' key financial metrics.