It proposes an alternative theory to explain macroeconomics equilibrium for a multi-sector economic period. It includes a brief derivation, numerical examples of closed and open economies (Appendix I), preliminar statistics of some national accounts data (Appendix II), a 2-Sectors Cash Flow Analysis (Appendix III), and short comments. Based on Marx's concepts of surplus and exploitation, it does not use Labor Value Theory and only applies market prices to input-output global or national accounts. Main points are: 1) Input-Output National Income Profit Accounts (IO-Nipas) portray an inner equilibrium in period flows - not reflected in standard Nipas mainly because they do not add exports to internal final production -. 2) Such balance depends on parameter "a", or period average markup, that ranges between 1 and 2 in the average but not necessarily in particular sectors, and is a function only of average surplus-rate. 3) Real market prices are considered the only functional and available expressions of value needed to measure flows, exchanges and aggregates, independently of the employed concept of value. Valuations of capitals or costs not transacted in the period market are not considered here, because they are not part of period flows. 4) Model relates microeconomic sectors with macroeconomic aggregates after a past period, and derives expressions for total transacted, total value-added, rates of profit, absolute surplus rates, and average markup factor. 5) Model can not predict, it only seeks to explain past economic periods. It might be used as a guide to orient economic policies and eventually, to set limits that dynamic models should fulfill.