This page contains information about data sources and limitations for SOI's Private Foundations study. Please visit the Domestic Private Foundations and Nonexempt Charitable Trust Statistics to access the annual data tables, articles, and publicly available microdata from the study. The private foundations statistics produced by the Statistics of Income (SOI) Division are based on a sample of Forms 990-PF that are filed with the Internal Revenue Service for a particular tax year. The SOI sample of private foundations is stratified based on both the size of fair market value of total assets and the type of organization (either a private foundation or an IRC section 4947(a)(1) nonexempt charitable trust). All returns filed by nonexempt charitable trusts, regardless of asset size, are selected for inclusion in the study. The private foundation sample is designed to provide reliable estimates of total assets and total revenue. To accomplish this, 100 percent of returns filed for foundations with fair market asset value of $10 million or more are included in the samples, since these organizations represent the vast majority of financial activity. The remaining foundation population is randomly selected for the sample at various rates, ranging from 1 percent to 100 percent, depending on asset size. See Figure A (below) for sample and population counts from the annual SOI studies of private foundations. Efforts are made to verify that organizations selected into the sample are properly classified as foundations or trusts. The relatively few foundations in the sample that are incorrectly selected as trusts are ultimately treated as foundations for the SOI statistics, and the relatively few trusts incorrectly sampled as foundations are also reclassified. However, the weights used for these organizations are based on the original sample selection classification. For a given tax year, SOI’s population estimates differ from the actual population of Forms 990-PF returns that post to the IRS Business Master File during the two-year sampling period. This results from sample code changes and the effects of returns that are “rejected” from the sample as part of the editing process. For example, foreign returns and duplicate filings by a single organization are included in the IRS counts of the actual population of Forms 990-PF filed, but are rejected from the SOI estimates. The data presented are obtained from returns as originally filed with IRS. In most cases, changes made to the original return because of administrative processing or audit procedures are not captured in the statistics. Changes made based on taxpayer amendment are captured, if available. The data are subjected to comprehensive testing and correction procedures in order to ensure statistical reliability and validity. A general discussion of the reliability of estimates based on samples, methods for evaluating both the magnitude of sampling and non-sampling error, and the precision of sample estimates can be found in the general Appendix of the most recent SOI Bulletin. Figure A Tax year Includes forms 990-PF processed between: All forms 990-PF: sample count All forms 990-PF: population count Private foundations: sample count Private foundations: population count Nonexempt charitable trusts: sample count Nonexempt charitable trusts: population count 1985 Jan. 1, 1986 - Dec. 31, 1987 1,930 32,691 1,930 32,691 – – 1986 Jan. 1, 1987 - Dec. 31, 1988 2,989 36,376 2,989 36,376 – – 1987 Jan. 1, 1988 - Dec. 31, 1989 4,923 36,600 4,923 36,600 – – 1988 Jan. 1, 1989 - Dec. 31, 1990 5,229 38,504 5,229 38,504 – – 1989 Jan. 1, 1990 - Dec. 31, 1991 5,651 42,702 4,280 39,812 1,371 2,890 1990 Jan. 1, 1991 - Dec. 31, 1992 5,956 44,118 4,541 41,231 1,415 2,887 1991 Jan. 1, 1992 - Dec. 31, 1993 5,665 45,414 4,455 42,526 1,210 2,888 1992 Jan. 1, 1993 - Dec. 31, 1994 5,852 46,698 4,662 43,767 1,190 2,931 1993 Jan. 1, 1994 - Dec. 31, 1995 5,419 48,223 4,253 45,570 1,166 2,653 1994 Jan. 1, 1995 - Dec. 31, 1996 5,948 50,487 5,065 47,971 883 2,516 1995 Jan. 1, 1996 - Dec. 31, 1997 6,388 52,070 5,579 49,823 809 2,247 1996 Jan. 1, 1997 - Dec. 31, 1998 7,552 55,315 6,261 52,297 1,291 3,018 1997 Jan. 1, 1998 - Dec. 31, 1999 8,412 60,533 7,208 57,463 1,204 3,070 1998 Jan. 1, 1999 - Dec. 31, 2000 8,758 64,595 7,783 61,425 975 3,170 1999 Jan. 1, 2000 - Dec. 31, 2001 8,045 68,367 7,039 65,254 1,006 3,113 2000 Jan. 1, 2001 - Dec. 31, 2002 8,202 72,605 7,236 69,575 966 3,030 2001 Jan. 1, 2002 - Dec. 31, 2003 6,465 75,643 5,644 72,644 821 2,999 2002 Jan. 1, 2003 - Dec. 31, 2004 6,301 79,333 5,507 76,307 794 3,026 2003 Jan. 1, 2004 - Dec. 31, 2005 10,537 81,962 7,302 78,727 3,235 3,235 2004 Jan. 1, 2005 - Dec. 31, 2006 11,451 84,216 7,805 80,570 3,646 3,646 2005 Jan. 1, 2006 - Dec. 31, 2007 12,003 86,896 8,244 83,137 3,759 3,759 2006 Jan. 1, 2007 - Dec. 31, 2008 12,741 88,886 9,112 85,257 3,629 3,629 2007 Jan. 1, 2008 - Dec. 31, 2009 12,972 91,220 9,407 87,655 3,565 3,565 2008 Jan. 1, 2009 - Dec. 31, 2010 14,693 100,997 8,533 94,837 6,160 6,160 2009 Jan. 1, 2010 - Dec. 31, 2011 16,900 102,811 10,652 96,563 6,248 6,248 2010 Jan. 1, 2011 - Dec. 31, 2012 17,619 103,802 11,003 97,186 6,616 6,616 2011 Jan. 1, 2012 - Dec. 31, 2013 17,624 103,865 11,092 97,333 6,532 6,532 2012 Jan. 1, 2013 - Dec. 31, 2014 18,331 104,451 11,822 97,942 6,509 6,509 2013 Jan. 1, 2014 - Dec. 31, 2015 19,307 105,350 12,678 98,721 6,629 6,629 2014 Jan. 1, 2015 - Dec. 31, 2016 19,573 107,399 13,030 100,856 6,543 6,543 2015 Jan. 1, 2016 - Dec. 31, 2017 19,367 109,220 12,973 102,826 6,394 6,394 2016 Jan. 1, 2017 - Dec. 31, 2018 20,145 110,799 13,663 104,317 6,482 6,482 2017 Jan. 1, 2018 - Dec. 31, 2019 20,847 112,528 14,519 106,200 6,328 6,328
