BLOG — Oct 01, 2021
US Monthly GDP Index for August 2021
By Ben Herzon and William Magee
Monthly GDP rose 1.0% in August, more than reversing a 0.5% decline in July that was revised down from the initial estimate of a 0.2% increase. The increase in August was largely accounted for by nonfarm inventory investment, as nonfarm inventories are estimated to have declined considerably less in August than they did in July. Final sales also contributed to the increase in GDP in August, with that gain more than accounted for by personal consumption expenditures. Implicit in our latest estimate of 2.2% (annualized) GDP growth in the third quarter is a 0.5% increase (not annualized) of GDP in September.
IHS Markit's index of Monthly GDP (MGDP) is a monthly indicator of real aggregate output that is conceptually consistent with real Gross Domestic Product (GDP) in the National Income and Product Accounts. The Monthly GDP Index is consistent with the NIPAs for two reasons: first, MGDP is calculated using much of the same underlying monthly source data that is used in the calculation of GDP. Second, the method of aggregation to arrive at MGDP is similar to that for official GDP. Growth of MGDP at the monthly frequency is determined primarily by movements in the underlying monthly source data, and growth of MGDP at the quarterly frequency is nearly identical to growth of real GDP.
