The phrase "substantial holdings" refers to a significant amount of assets or investments that someone or a company possesses. It means having a considerable amount of something valuable. Full definition
I currently have substantial holdings of preferred stocks this way, along with significant capital gains. (aaii.com)
On HDFC Mid cap, the fund currently has substantial holdings in large caps, which in my opinion, is a breach of the asset allocation mandate of being in mid caps for a minimum of 75 %. (unovest.co)
Activist investors with substantial holdings wield considerable influence over management often seeking to gain representation on the board. (investopedia.com)