NUVEEN CALIFORNIA SELECT TAX FREE INCOME PORTFOLIO

Regulatory Filings • Aug 29, 2017

N-Q 1 d427639dnq.htm NUVEEN CALIFORNIA SELECT TAX-FREE INCOME PORTFOLIO Nuveen California Select Tax-Free Income Portfolio

UNITED STATES SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

FORM N-Q

QUARTERLY SCHEDULE OF PORTFOLIO HOLDINGS OF REGISTERED MANAGEMENT INVESTMENT COMPANY

Investment Company Act file number 811-06623

Nuveen California Select Tax-Free Income Portfolio

(Exact name of registrant as specified in charter)

Nuveen Investments

333 West Wacker Drive, Chicago, Illinois 60606

(Address of principal executive offices) (Zip code)

Gifford R. Zimmerman

Vice President and Secretary

333 West Wacker Drive, Chicago, Illinois 60606

(Name and address of agent for service)

Registrant’s telephone number, including area code: 312-917-7700

Date of fiscal year end: March 31

Date of reporting period: June 30, 2017

Form N-Q is to be used by management investment companies, other than small business investment companies registered on Form N-5 (§§ 239.24 and 274.5 of this chapter), to file reports with the Commission, not later than 60 days after the close of the first and third fiscal quarters, pursuant to rule 30b1-5 under the Investment Company Act of 1940 (17 CFR 270.30b1-5). The Commission may use the information provided on Form N-Q in its regulatory, disclosure review, inspection, and policymaking roles.

A registrant is required to disclose the information specified by Form N-Q, and the Commission will make this information public. A registrant is not required to respond to the collection of information contained in Form N-Q unless the Form displays a currently valid Office of Management and Budget (“OMB”) control number. Please direct comments concerning the accuracy of the information collection burden estimate and any suggestions for reducing the burden to the Secretary, Securities and Exchange Commission, 450 Fifth Street, NW, Washington, DC 20549-0609. The OMB has reviewed this collection of information under the clearance requirements of 44 U.S.C. § 3507.

Item 1. Schedule of Investments

NXC

Nuveen California Select Tax-Free Income Portfolio

Portfolio of Investments June 30, 2017 (Unaudited)

| Principal
Amount (000) | Description
(1) | Optional
Call Provisions (2) | Ratings
(3) | Value |
| --- | --- | --- | --- | --- |
| | LONG-TERM
INVESTMENTS – 98.4% | | | |
| | MUNICIPAL
BONDS – 98.4% | | | |
| | Consumer
Staples – 6.4% | | | |
| $ 1,000 | California
County Tobacco Securitization Agency, Tobacco Settlement Asset-Backed Bonds, Gold Country Settlement Funding Corporation, Refunding Series 2006, 5.250%, 6/01/46 | 9/17
at 100.00 | CCC | $ 999,910 |
| 50 | California
County Tobacco Securitization Agency, Tobacco Settlement Asset-Backed Bonds, Sonoma County Tobacco Securitization Corporation, Series 2005, 4.250%, 6/01/21 | 9/17
at 100.00 | BBB+ | 50,011 |
| 1,095 | Golden
State Tobacco Securitization Corporation, California, Tobacco Settlement Asset-Backed Bonds, Senior Convertible Series 2007A-2, 5.300%, 6/01/37 | 6/22
at 100.00 | B | 1,113,133 |
| | Golden
State Tobacco Securitization Corporation, California, Tobacco Settlement Asset-Backed Bonds, Series 2007A-1: | | | |
| 775 | 5.000%,
6/01/33 | 9/17
at 100.00 | B+ | 778,673 |
| 660 | 5.750%,
6/01/47 | 9/17
at 100.00 | B3 | 664,778 |
| 1,500 | Tobacco
Securitization Authority of Northern California, Tobacco Settlement Asset-Backed Bonds, Series 2005A-1, 5.500%, 6/01/45 | 9/17
at 100.00 | B- | 1,490,820 |
| 1,000 | Tobacco
Securitization Authority of Southern California, Tobacco Settlement Asset-Backed Bonds, San Diego County Tobacco Asset Securitization Corporation, Senior Series 2006A, 5.000%, 6/01/37 | 9/17
at 100.00 | BB+ | 1,000,060 |
| 6,080 | Total
Consumer Staples | | | 6,097,385 |
| | Education
and Civic Organizations – 3.4% | | | |
| 195 | California
Educational Facilities Authority, Revenue Bonds, Santa Clara University, Series 2008A, 5.625%, 4/01/37 | 4/18
at 100.00 | Aa3 | 201,410 |
| 160 | California
Municipal Finance Authority, Charter School Revenue Bonds, Rocketship Education; Multiple Projects, Series 2014A, 7.250%, 6/01/43 | 6/22
at 102.00 | N/R | 181,939 |
| 60 | California
School Finance Authority, School Facility Revenue Bonds, Alliance for College-Ready Public Schools Project, Series 2016A, 5.000%, 7/01/46 | 7/25
at 100.00 | BBB | 64,397 |
| 385 | California
School Finance Authority, School Facility Revenue Bonds, Alliance for College-Ready Public Schools Project, Series 2016C, 5.000%, 7/01/46 | 7/25
at 101.00 | BBB | 415,762 |
| 250 | California
Statewide Communities Development Authority, School Facility Revenue Bonds, Alliance College-Ready Public Schools, Series 2011A, 7.000%, 7/01/46 | 7/21
at 100.00 | BBB- | 282,350 |
| 2,000 | University
of California, General Revenue Bonds, Limited Project Series 2016K, 4.000%, 5/15/46 | 5/26
at 100.00 | AA- | 2,095,900 |
| 3,050 | Total
Education and Civic Organizations | | | 3,241,758 |
| | Health
Care – 12.7% | | | |
| 1,000 | California
Health Facilities Financing Authority, California, Revenue Bonds, Sutter Health, Refunding Series 2016B, 5.000%, 11/15/46 | 11/26
at 100.00 | AA- | 1,150,880 |
| 2,500 | California
Health Facilities Financing Authority, California, Revenue Bonds, Sutter Health, Series 2016A, 5.000%, 11/15/41 | 11/25
at 100.00 | AA- | 2,853,850 |
| 115 | California
Health Facilities Financing Authority, Revenue Bonds, Lucile Salter Packard Children's Hospital, Series 2014A, 5.000%, 8/15/43 | 8/24
at 100.00 | AA | 128,869 |

| Principal
Amount (000) | Description
(1) | Optional
Call Provisions (2) | Ratings
(3) | Value |
| --- | --- | --- | --- | --- |
| | Health
Care (continued) | | | |
| $ 125 | California
Health Facilities Financing Authority, Revenue Bonds, Providence Health & Services, Refunding Series 2014A, 5.000%, 10/01/38 | 10/24
at 100.00 | AA- | $ 143,640 |
| 255 | California
Health Facilities Financing Authority, Revenue Bonds, Providence Health & Services, Series 2014B, 5.000%, 10/01/44 | 10/24
at 100.00 | AA- | 285,539 |
| 2,000 | California
Health Facilities Financing Authority, Revenue Bonds, Providence Saint Joseph Health, Refunding Series 2016A, 4.000%, 10/01/47 | 10/26
at 100.00 | AA- | 2,056,040 |
| 235 | California
Health Facilities Financing Authority, Revenue Bonds, Rady Children's Hospital - San Diego, Series 2011, 5.250%, 8/15/41 | 8/21
at 100.00 | AA | 257,851 |
| 35 | California
Municipal Finance Authority, Revenue Bonds, Eisenhower Medical Center, Series 2017A, 5.000%, 7/01/42 (WI/DD, Settling 7/06/17) | 7/27
at 100.00 | Baa2 | 39,330 |
| 130 | California
Municipal Finance Authority, Revenue Bonds, NorthBay Healthcare Group, Series 2017A, 5.250%, 11/01/41 | 11/26
at 100.00 | BBB- | 146,325 |
| 350 | California
Statewide Communities Development Authority, California, Revenue Bonds, Loma Linda University Medical Center, Series 2014A, 5.250%, 12/01/34 | 12/24
at 100.00 | BB+ | 386,578 |
| | California
Statewide Communities Development Authority, California, Revenue Bonds, Loma Linda University Medical Center, Series 2016A: | | | |
| 825 | 5.000%,
12/01/46 | 6/26
at 100.00 | BB+ | 890,076 |
| 540 | 5.250%,
12/01/56 | 6/26
at 100.00 | BB+ | 589,270 |
| 425 | California
Statewide Community Development Authority, Revenue Bonds, Children's Hospital of Los Angeles, Series 2007, 5.000%, 8/15/47 | 8/17
at 100.00 | BBB+ | 427,257 |
| 1,100 | Palomar
Pomerado Health Care District, California, Certificates of Participation, Series 2010, 6.000%, 11/01/41 | 11/20
at 100.00 | BBB- | 1,197,504 |
| 670 | San
Buenaventura, California, Revenue Bonds, Community Memorial Health System, Series 2011, 7.500%, 12/01/41 | 12/21
at 100.00 | BB+ | 785,414 |
| 800 | Upland,
California, Certificates of Participation, San Antonio Community Hospital, Series 2011, 6.500%, 1/01/41 | 1/21
at 100.00 | BBB+ | 898,672 |
| 11,105 | Total
Health Care | | | 12,237,095 |
| | Housing/Multifamily – 1.0% | | | |
| 360 | California
Municipal Finance Authority, Mobile Home Park Revenue Bonds, Caritas Projects Series 2010A, 6.400%, 8/15/45 | 8/20
at 100.00 | BBB | 391,655 |
| 395 | California
Municipal Finance Authority, Mobile Home Park Revenue Bonds, Caritas Projects Series 2012A, 5.500%, 8/15/47 | 8/22
at 100.00 | BBB | 436,238 |
| | California
Municipal Finance Authority, Mobile Home Park Senior Revenue Bonds, Caritas Affordable Housing, Inc. Projects, Series 2014A: | | | |
| 25 | 5.250%,
8/15/39 | 8/24
at 100.00 | BBB | 27,668 |
| 65 | 5.250%,
8/15/49 | 8/24
at 100.00 | BBB | 71,507 |
| 845 | Total
Housing/Multifamily | | | 927,068 |
| | Industrials – 1.1% | | | |
| 1,015 | California
Pollution Control Financing Authority, Solid Waste Disposal Revenue Bonds, Republic Services Inc., Series 2002C, 5.250%, 6/01/23 (Alternative Minimum Tax) (Mandatory Put 12/01/17) | 12/17
at 100.00 | BBB+ | 1,029,931 |
| | Tax
Obligation/General – 24.6% | | | |
| 1,000 | California
State, General Obligation Bonds, Various Purpose Refunding Series 2015, 5.000%, 8/01/34 | 8/25
at 100.00 | AA- | 1,170,810 |

| Principal
Amount (000) | Description
(1) | Optional
Call Provisions (2) | Ratings
(3) | Value |
| --- | --- | --- | --- | --- |
| | Tax
Obligation/General (continued) | | | |
| $ 1,650 | California
State, General Obligation Bonds, Various Purpose Series 2009, 5.500%, 11/01/39 | 11/19
at 100.00 | AA- | $ 1,811,452 |
| 1,965 | California
State, General Obligation Bonds, Various Purpose Series 2011, 5.000%, 10/01/41 | 10/21
at 100.00 | AA- | 2,204,121 |
| 2,000 | California
State, General Obligation Bonds, Various Purpose Series 2012, 5.250%, 4/01/35 | 4/22
at 100.00 | AA- | 2,293,240 |
| | Golden
West Schools Financing Authority, California, General Obligation Revenue Refunding Bonds, School District Program, Series 1999A: | | | |
| 2,375 | 0.000%,
8/01/17  –  NPFG Insured | No
Opt. Call | A | 2,373,052 |
| 2,345 | 0.000%,
2/01/18  –  NPFG Insured | No
Opt. Call | A | 2,329,875 |
| 1,080 | Mountain
View-Los Altos Union High School District, Santa Clara County, California, General Obligation Bonds, Capital Appreciation Series 1997C, 0.000%, 5/01/18  –  NPFG Insured | No
Opt. Call | Aaa | 1,071,328 |
| 7,575 | Palomar
Pomerado Health, California, General Obligation Bonds, Convertible Capital Appreciation, Election 2004 Series 2010A, 0.000%, 8/01/34 | No
Opt. Call | A+ | 3,724,855 |
| 1,000 | San
Benito High School District, San Benito and Santa Clara Counties, California, General Obligation Bonds, 2016 Election Series 2017, 5.250%, 8/01/46 | 8/27
at 100.00 | Aa3 | 1,212,000 |
| 8,075 | San
Bernardino Community College District, California, General Obligation Bonds, Election of 2008 Series 2009B, 0.000%, 8/01/44 | No
Opt. Call | Aa2 | 2,633,338 |
| 1,000 | Santa
Barbara Unified School District, Santa Barbara County, California, General Obligation Bonds, Election of 2016 Series 2017A, 4.000%, 8/01/41 | 8/27
at 100.00 | Aa2 | 1,055,220 |
| 2,000 | West
Hills Community College District, California, General Obligation Bonds, School Facilities Improvement District 3, 2008 Election Series 2011, 7.400%, 8/01/38  –  AGM Insured | 8/31
at 100.00 | AA | 1,793,020 |
| 32,065 | Total
Tax Obligation/General | | | 23,672,311 |
| | Tax
Obligation/Limited – 17.5% | | | |
| 1,000 | Bell
Community Redevelopment Agency, California, Tax Allocation Bonds, Bell Project Area, Series 2003, 5.625%, 10/01/33  –  RAAI Insured | 9/17
at 100.00 | AA | 1,002,100 |
| 2,000 | California
State Public Works Board, Lease Revenue Bonds, Department of Corrections & Rehabilitation, Various Correctional Facilities Series 2013F, 5.250%, 9/01/33 | 9/23
at 100.00 | A+ | 2,362,700 |
| 360 | Chino
Redevelopment Agency, California, Merged Chino Redevelopment Project Area Tax Allocation Bonds, Series 2006, 5.000%, 9/01/38  –  AMBAC Insured | 9/17
at 100.00 | A | 361,951 |
| 1,000 | Fontana
Public Financing Authority, California, Tax Allocation Revenue Bonds, North Fontana Redevelopment Project, Series 2005A, 5.000%, 10/01/32  –  AMBAC Insured | 9/17
at 100.00 | A | 1,002,660 |
| 270 | Fontana
Redevelopment Agency, San Bernardino County, California, Tax Allocation Bonds, Jurupa Hills Redevelopment Project, Refunding Series 1997A, 5.500%, 10/01/27 | 10/17
at 100.00 | A | 272,970 |
| 3,000 | Golden
State Tobacco Securitization Corporation, California, Enhanced Tobacco Settlement Asset-Backed Revenue Bonds, Refunding Series 2015A, 5.000%, 6/01/40 | 6/25
at 100.00 | A+ | 3,420,090 |
| 1,215 | Los
Angeles Community Redevelopment Agency, California, Lease Revenue Bonds, Vermont Manchester Social Services Project, Series 2005, 5.000%, 9/01/37  –  AMBAC Insured | 9/17
at 100.00 | Aa2 | 1,229,058 |
| 1,000 | Los
Angeles County Metropolitan Transportation Authority, California, Measure R Sales Tax Revenue Bonds, Senior Series 2016A, 5.000%, 6/01/38 | 6/26
at 100.00 | AAA | 1,177,740 |
| 135 | National
City Community Development Commission, California, Tax Allocation Bonds, National City Redevelopment Project, Series 2011, 6.500%, 8/01/24 | 8/21
at 100.00 | A | 161,603 |
| 1,000 | Norco
Redevelopment Agency, California, Tax Allocation Bonds, Project Area 1, Series 2009, 7.000%, 3/01/34 | 3/18
at 100.00 | A+ | 1,039,120 |

| Principal
Amount (000) | Description
(1) | Optional
Call Provisions (2) | Ratings
(3) | Value |
| --- | --- | --- | --- | --- |
| | Tax
Obligation/Limited (continued) | | | |
| $ 50 | Novato
Redevelopment Agency, California, Tax Allocation Bonds, Hamilton Field Redevelopment Project, Series 2011, 6.750%, 9/01/40 | 9/21
at 100.00 | BBB+ | $ 58,926 |
| 60 | Patterson
Public Finance Authority, California, Revenue Bonds, Community Facilities District 2001-1, Subordinate Lien Series 2013B, 5.875%, 9/01/39 | 9/23
at 100.00 | N/R | 65,761 |
| | Patterson
Public Financing Authority, California, Revenue Bonds, Community Facilities District 2001-1, Senior Series 2013A: | | | |
| 350 | 5.250%,
9/01/30 | 9/23
at 100.00 | N/R | 379,190 |
| 320 | 5.750%,
9/01/39 | 9/23
at 100.00 | N/R | 348,202 |
| 30 | Riverside
County Redevelopment Agency, California, Tax Allocation Bonds, Jurupa Valley Project Area, Series 2011B, 6.500%, 10/01/25 | 10/21
at 100.00 | A | 35,591 |
| 425 | Sacramento
City Financing Authority, California, Lease Revenue Refunding Bonds, Series 1993A, 5.400%, 11/01/20  –  NPFG Insured | No
Opt. Call | A+ | 453,904 |
| 20 | San
Clemente, California, Special Tax Revenue Bonds, Community Facilities District 2006-1 Marblehead Coastal, Series 2015, 5.000%, 9/01/40 | 9/25
at 100.00 | N/R | 21,906 |
| 1,365 | San
Diego County Regional Transportation Commission, California, Sales Tax Revenue Bonds, Refunding Series 2012A, 5.000%, 4/01/42 | 4/22
at 100.00 | AAA | 1,551,746 |
| 65 | San
Francisco City and County Redevelopment Agency Successor Agency, California, Special Tax Bonds, Community Facilities District 7, Hunters Point Shipyard Phase One Improvements, Refunding Series 2014, 5.000%, 8/01/39 | 8/24
at 100.00 | N/R | 70,307 |
| 615 | San
Jose Redevelopment Agency, California, Tax Allocation Bonds, Merged Area Redevelopment Project, Series 2006C, 5.000%, 8/01/25  –  NPFG Insured | 8/17
at 100.00 | A+ | 617,159 |
| 40 | Signal
Hill Redevelopment Agency, California, Project 1 Tax Allocation Bonds, Series 2011, 7.000%, 10/01/26 | 4/21
at 100.00 | N/R | 45,747 |
| 1,000 | Virgin
Islands Public Finance Authority, Matching Fund Loan Notes Revenue Bonds, Series 2012A, 5.000%, 10/01/32  –  AGM Insured | 10/22
at 100.00 | AA | 1,053,680 |
| 70 | Yorba
Linda Redevelopment Agency, Orange County, California, Tax Allocation Revenue Bonds, Yorba Linda Redevelopment Project, Subordinate Lien Series 2011A, 6.500%, 9/01/32 | 9/21
at 100.00 | A- | 82,508 |
| 15,390 | Total
Tax Obligation/Limited | | | 16,814,619 |
| | Transportation – 6.7% | | | |
| 530 | Foothill/Eastern
Transportation Corridor Agency, California, Toll Road Revenue Bonds, Refunding Junior Lien Series 2013C, 6.500%, 1/15/43 | 1/24
at 100.00 | BB+ | 635,428 |
| | Foothill/Eastern
Transportation Corridor Agency, California, Toll Road Revenue Bonds, Refunding Series 2013A: | | | |
| 1,000 | 5.000%,
1/15/42  –  AGM Insured | 1/24
at 100.00 | AA | 1,118,610 |
| 1,170 | 5.750%,
1/15/46 | 1/24
at 100.00 | BBB- | 1,348,331 |
| 1,175 | 6.000%,
1/15/53 | 1/24
at 100.00 | BBB- | 1,353,412 |
| 800 | Long
Beach, California, Harbor Revenue Bonds, Series 2015D, 5.000%, 5/15/42 | 5/25
at 100.00 | AA | 924,200 |
| 955 | Port
of Oakland, California, Revenue Bonds, Refunding Series 2012P, 5.000%, 5/01/31 (Alternative Minimum Tax) | 5/22
at 100.00 | A+ | 1,063,087 |
| 5,630 | Total
Transportation | | | 6,443,068 |
| | U.S.
Guaranteed – 8.9% (4) | | | |
| 2,805 | California
Educational Facilities Authority, Revenue Bonds, Santa Clara University, Series 2008A, 5.625%, 4/01/37 (Pre-refunded 4/01/18) | 4/18
at 100.00 | N/R
(4) | 2,905,784 |
| 210 | California
State Public Works Board, Lease Revenue Bonds, Department of Corrections, Calipatria State Prison, Series 1991A, 6.500%, 9/01/17  –  NPFG Insured (ETM) | No
Opt. Call | A+
(4) | 212,039 |

| Principal
Amount (000) | Description
(1) | Optional
Call Provisions (2) | Ratings
(3) | Value |
| --- | --- | --- | --- | --- |
| | U.S.
Guaranteed (4) (continued) | | | |
| $ 1,500 | California
State Public Works Board, Lease Revenue Bonds, Various Capital Projects, Series 2009-I, 6.375%, 11/01/34 (Pre-refunded 11/01/19) | 11/19
at 100.00 | Aaa | $ 1,685,670 |
| 1,000 | Imperial
Irrigation District, California, Electric System Revenue Bonds, Refunding Series 2011A, 5.500%, 11/01/41 (Pre-refunded 11/01/20) | 11/20
at 100.00 | AA-
(4) | 1,145,370 |
| | Irvine
Unified School District Financing Authority, Orange County, California, Special Tax Bonds, Group II, Series 2006A: | | | |
| 35 | 5.000%,
9/01/26 (Pre-refunded 9/01/17) | 9/17
at 100.00 | N/R
(4) | 36,648 |
| 80 | 5.125%,
9/01/36 (Pre-refunded 9/01/17) | 9/17
at 100.00 | N/R
(4) | 83,883 |
| 540 | Loma
Linda, California, Hospital Revenue Bonds, Loma Linda University Medical Center, Series 2008A, 8.250%, 12/01/38 (Pre-refunded 12/01/17) | 12/17
at 100.00 | BB
(4) | 556,697 |
| 500 | Palomar
Pomerado Health Care District, California, Certificates of Participation, Series 2009, 6.625%, 11/01/29 (Pre-refunded 11/01/19) | 11/19
at 100.00 | Ba1
(4) | 564,835 |
| 415 | Pittsburg
Redevelopment Agency, California, Tax Allocation Bonds, Los Medanos Community Development Project, Refunding Series 2008A, 6.500%, 9/01/28 (Pre-refunded 9/01/18) | 9/18
at 100.00 | N/R
(4) | 442,116 |
| 160 | Rancho
Santa Fe CSD Financing Authority, California, Revenue Bonds, Superior Lien Series 2011A, 5.750%, 9/01/30 (Pre-refunded 9/01/21) | 9/21
at 100.00 | A-
(4) | 189,539 |
| 25 | San
Francisco Redevelopment Finance Authority, California, Tax Allocation Revenue Bonds, Mission Bay North Redevelopment Project, Series 2011C, 6.750%, 8/01/41 (Pre-refunded 2/01/21) | 2/21
at 100.00 | A-
(4) | 29,933 |
| | San
Francisco Redevelopment Financing Authority, California, Tax Allocation Revenue Bonds, Mission Bay South Redevelopment Project, Series 2011D: | | | |
| 25 | 7.000%,
8/01/33 (Pre-refunded 2/01/21) | 2/21
at 100.00 | BBB+
(4) | 30,143 |
| 30 | 7.000%,
8/01/41 (Pre-refunded 2/01/21) | 2/21
at 100.00 | BBB+
(4) | 36,171 |
| 225 | San
Mateo Union High School District, San Mateo County, California, Certificates of Participation, Phase 1, Series 2007A, 5.000%, 12/15/30 (Pre-refunded 12/15/17)  –  AMBAC Insured | 12/17
at 100.00 | N/R
(4) | 229,390 |
| 360 | Turlock
Public Financing Authority, California, Tax Allocation Revenue Bonds, Series 2011, 7.500%, 9/01/39 (Pre-refunded 3/01/21) | 3/21
at 100.00 | A-
(4) | 441,324 |
| 7,910 | Total
U.S. Guaranteed | | | 8,589,542 |
| | Utilities – 0.9% | | | |
| 645 | Long
Beach Bond Finance Authority, California, Natural Gas Purchase Revenue Bonds, Series 2007A, 5.500%, 11/15/37 | No
Opt. Call | A | 826,290 |
| | Water
and Sewer – 15.2% | | | |
| 1,000 | Bay
Area Water Supply and Conservation Agency, California, Revenue Bonds, Capital Cost Recovery Prepayment Program, Series 2013A, 5.000%, 10/01/34 | 4/23
at 100.00 | AA- | 1,145,840 |
| 1,480 | California
Infrastructure and Economic Development Bank, Clean Water State Revolving Fund Revenue Bonds, Green Series 2017, 5.000%, 10/01/33 | 4/27
at 100.00 | AAA | 1,802,714 |
| | California
Pollution Control Financing Authority, Water Furnishing Revenue Bonds, Poseidon Resources Channelside LP Desalination Project, Series 2012: | | | |
| 375 | 5.000%,
7/01/37 (Alternative Minimum Tax) | 7/22
at 100.00 | Baa3 | 401,231 |
| 1,160 | 5.000%,
11/21/45 (Alternative Minimum Tax) | 7/22
at 100.00 | Baa3 | 1,240,481 |
| 2,000 | Escondido
Joint Powers Financing Authority, California, Revenue Bonds, Water System Financing, Series 2012, 5.000%, 9/01/41 | 3/22
at 100.00 | AA- | 2,264,920 |
| 2,000 | Irvine
Ranch Water District, California, Certificates of Participation, Irvine Ranch Water District Series 2016, 5.000%, 3/01/41 | 9/26
at 100.00 | AAA | 2,357,120 |

| Principal
Amount (000) | Description
(1) | Optional
Call Provisions (2) | Ratings
(3) | Value |
| --- | --- | --- | --- | --- |
| | Water
and Sewer (continued) | | | |
| $ 1,970 | Los
Angeles Department of Water and Power, California, Waterworks Revenue Bonds, Series 2014A, 5.000%, 7/01/44 | 7/24
at 100.00 | AA+ | $ 2,268,199 |
| 1,000 | Los
Angeles Department of Water and Power, California, Waterworks Revenue Bonds, Series 2017A, 5.000%, 7/01/41 | 1/27
at 100.00 | AA+ | 1,180,620 |
| 620 | Los
Angeles, California, Wastewater System Revenue Bonds, Green Subordinate Lien Series 2017A, 5.250%, 6/01/47 | 6/27
at 100.00 | AA | 753,151 |
| 1,000 | Santa
Clara Valley Water District, California, Water System Revenue Bonds, Refunding Series 2016A, 5.000%, 6/01/31 | 12/25
at 100.00 | Aa1 | 1,201,340 |
| 12,605 | Total
Water and Sewer | | | 14,615,616 |
| $ 96,340 | Total
Long-Term Investments (cost $86,350,691) | | | 94,494,683 |
| | Other
Assets Less Liabilities – 1.6% | | | 1,557,775 |
| | Net
Assets – 100% | | | $ 96,052,458 |

Fair Value Measurements

Fair value is defined as the price that would be received upon selling an investment or transferring a liability in an orderly transaction to an independent buyer in the principal or most advantageous market for the investment. A three-tier hierarchy is used to maximize the use of observable market data and minimize the use of unobservable inputs and to establish classification of fair value measurements for disclosure purposes. Observable inputs reflect the assumptions market participants would use in pricing the asset or liability. Observable inputs are based on market data obtained from sources independent of the reporting entity. Unobservable inputs reflect the reporting entity’s own assumptions about the assumptions market participants would use in pricing the asset or liability. Unobservable inputs are based on the best information available in the circumstances. The following is a summary of the three-tiered hierarchy of valuation input levels.

Level 1 – Inputs are unadjusted and prices are determined using quoted prices in active markets for identical securities.

Level 2 – Prices are determined using other significant observable inputs (including quoted prices for similar securities, interest rates, prepayment speeds, credit risk, etc.).

Level 3 – Prices are determined using significant unobservable inputs (including management’s assumptions in determining the fair value of investments).

The inputs or methodologies used for valuing securities are not an indication of the risks associated with investing in those securities. The following is a summary of the Fund’s fair value measurements as of the end of the reporting period:

| | Level
1 | Level
2 | Level
3 | Total |
| --- | --- | --- | --- | --- |
| Long-Term
Investments: | | | | |
| Municipal
Bonds | $ — | $94,494,683 | $ — | $94,494,683 |

Income Tax Information

The following information is presented on an income tax basis. Differences between amounts for financial statement and federal income tax purposes are primarily due to timing differences in recognizing taxable market discount, timing differences in recognizing certain gains and losses on investment transactions and the treatment of investments in inverse floating rate securities reflected as financing transactions, if any. To the extent that differences arise that are permanent in nature, such amounts are reclassified within the capital accounts on the Statement of Assets and Liabilities presented in the annual report, based on their federal tax basis treatment; temporary differences do not require reclassification. Temporary and permanent differences do not impact the net asset value of the Fund.

As of June 30, 2017, the cost of investments was $86,297,319.

Gross unrealized appreciation and gross unrealized depreciation of investments as of June 30, 2017, were as follows:

| Gross
unrealized: | |
| --- | --- |
| Appreciation | $8,303,805 |
| Depreciation | (106,441) |
| Net
unrealized appreciation (depreciation) of investments | $8,197,364 |

| (1) | All
percentages shown in the Portfolio of Investments are based on net assets. |
| --- | --- |
| (2) | Optional
Call Provisions: Dates (month and year) and prices of the earliest optional call or redemption. There may be other call provisions at varying prices at later dates. Certain mortgage-backed securities may be subject to periodic principal paydowns. |
| (3) | For
financial reporting purposes, the ratings disclosed are the highest of Standard & Poor’s Group (“Standard & Poor’s”), Moody’s Investors Service, Inc. (“Moody’s”) or Fitch, Inc.
(“Fitch”) rating. This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Ratings below BBB by Standard & Poor’s, Baa by Moody’s or BBB by Fitch are
considered to be below investment grade. Holdings designated N/R are not rated by any of these national rating agencies. |
| (4) | Backed
by an escrow or trust containing sufficient U.S. Government or U.S. Government agency securities, which ensure the timely payment of principal and interest. Certain bonds backed by U.S. Government or agency securities are regarded as having an
implied rating equal to the rating of such securities. |
| (ETM) | Escrowed
to maturity. |
| (WI/DD) | Investment,
or portion of investment, purchased on a when-issued or delayed delivery basis. |

Item 2. Controls and Procedures.

a. The registrant’s principal executive and principal financial officers, or persons performing similar functions, have concluded that the registrant’s disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940, as amended (the “1940 Act”) (17 CFR 270.30a-3(c))) are effective, as of a date within 90 days of the filing date of this report that includes the disclosure required by this paragraph, based on their evaluation of the controls and procedures required by Rule 30a-3(b) under the 1940 Act (17 CFR 270.30a-3(b)) and Rule 13a-15(b) or 15d-15(b) under the Securities Exchange Act of 1934 (17 CFR 240.13a-15(b) or 240.15d-15(b)).

b. There were no changes in the registrant’s internal control over financial reporting (as defined in Rule 30a-3(d) under the 1940 Act (17 CFR 270.30a-3(d)) that occurred during the registrant’s last fiscal quarter that have materially affected, or are reasonably likely to materially affect, the registrant’s internal control over financial reporting.

Item 3. Exhibits.

File as exhibits as part of this Form a separate certification for each principal executive officer and principal financial officer of the registrant as required by Rule 30a-2(a) under the 1940 Act (17 CFR 270.30a-2(a)), exactly as set forth below: See EX-99 CERT attached hereto.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

(Registrant)	Nuveen California Select Tax-Free Income Portfolio
By (Signature and Title)	/s/ Gifford R.
Zimmerman
	Gifford R. Zimmerman
	Vice President and Secretary

Date: August 29, 2017

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

| By (Signature and Title) | /s/ Cedric H.
Antosiewicz |
| --- | --- |
| | Cedric H. Antosiewicz |
| | Chief Administrative Officer (principal executive officer) |
| Date: August 29, 2017 | |
| By (Signature and Title) | /s/ Stephen D.
Foy |
| | Stephen D. Foy |
| | Vice President and Controller (principal financial officer) |
| Date: August 29, 2017 | |