Beginning in 1996, level estimated by FOF Section as the sum of the market value of nonfinancial C-corporations and S-corporations. The market value of S-corporations is estimated by multiplying the net worth data of S-corporations in nonfinancial industries (identified by 2-digit NAICS codes) from the IRS, SOI Table S-Corporation Returns: Balance Sheet and Income Statement Items, by Major Industry, by the average ratio of market value to net worth from Standard and Poor's Compustat for public companies in the same nonfinancial industries. The market value of C-corporations is estimated by multiplying the revenue data of companies that appear on Forbes' annual list of America's Largest Private Companies by the ratio of total market value to total revenue of public companies from Standard and Poor's Compustat with similar industry, employment, and revenue profiles. The total market value of C-corporations is split between financial and nonfinancial corporations using the same splits available from the S-corporations calculations. The total market value of C-corporations and S-corporations is adjusted downward by 25 percent to reflect the lack of liquidity of closely held shares. Prior to 1996, nonfinancial business' closely held equity is included with nonfinancial business' public corporate equities (FOF series FL103164113 ). Series has no flows. Data for the most recent ten years show no significant seasonality.