A few decades ago, worldwide, buyers and sellers were individual investors, such as wealthy businessmen, with long family histories (and emotional ties) to particular corporations. Over time, markets have become more "institutionalized"; buyers and sellers are largely institutions (e.g., pension funds, insurance companies, mutual funds, index funds, exchange-traded funds, hedge funds, investor groups, banks and various other financial institutions). The rise of the institutional investor has brought with it some improvements in market operations. Thus, the government was responsible for "fixed" (and exorbitant) fees being markedly reduced for the 'small' investor, but only after the large institutions had managed to break the brokers' solid front on fees. (They then went to 'negotiated' fees, but only for large institutions.
However, corporate governance (at least in the West) has been very much adversely affected by the rise of (largely 'absentee') institutional 'owners'.