This article is first in a series that provides an ongoing analysis of the changes made to BAMCO Inc.'s 13F stock portfolio on a quarterly basis. It is based on Ron Baron's regulatory 13F Form filed on 02/18/2020. The 13F portfolio value increased ~8% from $24.31B to $26.19B this quarter. The holdings are diversified with recent 13F reports showing around 350 positions. There are 48 securities that are significantly large (more than ~0.5% of the portfolio each) and they are the focus of this article. The largest five stakes are CoStar Group (CSGP), Vail Resorts