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 |