Are shareholder payouts a tool for reallocating capital from large, established corporations to the newer, smaller firms with better prospects for growth? If so, we should see this reflected in the investment figures — the shareholder revolution of the 1980s, and the more recent growth of activist investors, should be associated with a shift of investment away from big incumbent firms. Do we see this?
As a simple test, we can look at the share of corporate investment accounted for by smaller and younger firms. And the answer this exercise suggests is, No. Within the corporate sector, there is also no sign of capital being allocated to new sectors and smaller firms. The following figures show the share of total corporate investment accounted for by young firms, defined as those listed for less than five years; and by small firms, defined as those with sales below the median sales for listed corporations in that year. 
The share of investment accounted for newer firms fluctuates between 5 and 20 percent of the total, peaking periodically when large numbers of new firms enter the markets.  The most recent such peak came in tech boom period of the late 1990s, as one might expect. But the young-firm investment share shows no upward trend, and since the recession has been stuck at its lowest level of the postwar period. As for the the share of investment accounted for small firms, it has steadily declined since the 1950s — apart from, again, a temporary spike during the tech-boom period. Like the investment share of newer firms, the investment share of small firms is now at its lowest level ever.
We come to a similar conclusion if we look at the share of investment accounted for by noncorporate businesses. Partnerships, sole proprietorships and other noncorporate businesses accounted for close to 20 percent of US fixed investment in the 1960s and 1970s, but have accounted for a steady 12 percent of fixed investment over the past 25 years. So the funds flowing out of large corporations sector are not financing increased investment in smaller, younger corporations, or in the noncorporate sector either.
This is not really surprising. Smaller and younger businesses are mainly dependent on bank loans, and shareholder payouts don’t increase bank lending capacity in any direct way. More broadly, it’s hard to see evidence that potential funders of new businesses are liquidity-constrained. Higher payouts presumably do contribute to higher stock prices, and perhaps marginally to lower bond yields, but any connection with financing for new businesses seems tenuous at best.
In any case, whatever the shareholder revolution has accomplished, there does no seem to have been any reallocation of capital to smaller, growing firms. Capital accumulation in the United States is more concentrated in large established corporations than ever.
 Data is from Compustat, a database that assembles all the income, cashflow and balance sheet statements published since 1950 by corporations listed on US markets. I’ve excluded the financial sector, defined as 2-digit NAICS 52 and 53 and SIC 60-69. Investment is capital expenditure plus R&D.
 I suspect the late-80s peak is an artifact of the many changes of ownership in that period, which are hard to distinguish from new listings.