Unassociated Document
 
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)
 

Kevin J. McCarthy
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:            3/31          
 
Date of reporting period:         6/30/15         
 
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
 
 
   
Portfolio of Investments
      
           
   
Nuveen California Select Tax-Free Income Portfolio (NXC)
      
   
June 30, 2015 (Unaudited)
      
 
 
Principal
    
Optional Call
    
Amount (000)
  
Description (1)
Provisions (2)
Ratings (3)
Value
   
LONG-TERM INVESTMENTS – 95.9%
      
           
   
MUNICIPAL BONDS – 95.9%
      
           
   
Consumer Staples – 3.7%
      
$         75
  
California County Tobacco Securitization Agency, Tobacco Settlement Asset-Backed Bonds,
9/15 at 100.00
BBB+
$       74,148
   
Sonoma County Tobacco Securitization Corporation, Series 2005, 4.250%, 6/01/21
      
185
  
California County Tobacco Securitization Agency, Tobacco Settlement Asset-Backed Revenue
9/15 at 100.00
Aa1
184,996
   
Bonds, Fresno County Tobacco Funding Corporation, Series 2002, 5.625%, 6/01/23
      
1,450
  
Golden State Tobacco Securitization Corporation, California, Tobacco Settlement Asset-Backed
6/17 at 100.00
B
1,202,877
   
Bonds, Series 2007A-1, 5.000%, 6/01/33
      
1,095
  
Golden State Tobacco Securitization Corporation, California, Tobacco Settlement Asset-Backed
6/22 at 100.00
B
872,868
   
Bonds, Series 2007A-2, 5.300%, 6/01/37
      
1,500
  
Tobacco Securitization Authority of Northern California, Tobacco Settlement Asset-Backed
9/15 at 100.00
B–
1,199,145
   
Bonds, Series 2005A-1, 5.500%, 6/01/45
      
4,305
  
Total Consumer Staples
    
3,534,034
   
Education and Civic Organizations – 4.0%
      
3,000
  
California Educational Facilities Authority, Revenue Bonds, Santa Clara University, Series
4/18 at 100.00
Aa3
3,309,960
   
2008A, 5.625%, 4/01/37
      
20
  
California Educational Facilities Authority, Revenue Bonds, University of Redlands, Series
10/15 at 100.00
A3
20,074
   
2005A, 5.000%, 10/01/35
      
160
  
California Municipal Finance Authority, Charter School Revenue Bonds, Rocketship
6/22 at 102.00
N/R
180,493
   
Education, Multiple Projects, Series 2014A , 7.250%, 6/01/43
      
250
  
California Statewide Communities Development Authority, School Facility Revenue Bonds,
7/21 at 100.00
BBB–
286,427
   
Alliance College-Ready Public Schools, Series 2011A, 7.000%, 7/01/46
      
3,430
  
Total Education and Civic Organizations
    
3,796,954
   
Health Care – 5.6%
      
115
  
California Health Facilities Financing Authority, Revenue Bonds, Lucile Salter Packard
8/24 at 100.00
AA
127,046
   
Children’s Hospital, Series 2014A, 5.000%, 8/15/43
      
125
  
California Health Facilities Financing Authority, Revenue Bonds, Providence Health & Services,
10/24 at 100.00
AA
138,350
   
Series 2014A, 5.000%, 10/01/38
      
255
  
California Health Facilities Financing Authority, Revenue Bonds, Providence Health & Services,
10/24 at 100.00
AA
280,760
   
Series 2014B, 5.000%, 10/01/44
      
235
  
California Health Facilities Financing Authority, Revenue Bonds, Rady Children’s Hospital –
8/21 at 100.00
AA–
259,189
   
San Diego, Series 2011, 5.250%, 8/15/41
      
425
  
California Statewide Community Development Authority, Revenue Bonds, Childrens Hospital of
8/17 at 100.00
BBB+
440,861
   
Los Angeles, Series 2007, 5.000%, 8/15/47
      
545
  
California Statewide Community Development Authority, Revenue Bonds, Kaiser Permanente
8/16 at 100.00
A+
567,955
   
System, Series 2001C, 5.250%, 8/01/31
      
500
  
Palomar Pomerado Health Care District, California, Certificates of Participation, Series 2009,
11/19 at 100.00
Ba1
553,840
   
6.625%, 11/01/29
      
1,100
  
Palomar Pomerado Health Care District, California, Certificates of Participation, Series 2010,
11/20 at 100.00
Ba1
1,166,715
   
6.000%, 11/01/41
      
670
  
San Buenaventura, California, Revenue Bonds, Community Memorial Health System, Series 2011,
12/21 at 100.00
BB
810,646
   
7.500%, 12/01/41
      
800
  
Upland, California, Certificates of Participation, San Antonio Community Hospital, Series 2011,
1/21 at 100.00
A–
919,400
   
6.500%, 1/01/41
      
4,770
  
Total Health Care
    
5,264,762
   
Housing/Multifamily – 1.0%
      
370
  
California Municipal Finance Authority, Mobile Home Park Revenue Bonds, Caritas Projects
8/20 at 100.00
BBB
405,376
   
Series 2010A, 6.400%, 8/15/45
      
395
  
California Municipal Finance Authority, Mobile Home Park Revenue Bonds, Caritas Projects
8/22 at 100.00
BBB
423,397
   
Series 2012A, 5.500%, 8/15/47
      
   
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
26,932
65
  
5.250%, 8/15/49
8/24 at 100.00
BBB
69,839
855
  
Total Housing/Multifamily
    
925,544
   
Housing/Single Family – 0.0%
      
25
  
California Housing Finance Agency, Home Mortgage Revenue Bonds, Series 2006H, 5.750%,
2/16 at 100.00
A
26,021
   
8/01/30 – FGIC Insured (Alternative Minimum Tax)
      
   
Industrials – 1.2%
      
1,015
  
California Pollution Control Financing Authority, Solid Waste Disposal Revenue Bonds, Republic
No Opt. Call
BBB+
1,089,521
   
Services Inc., Series 2002C, 5.250%, 6/01/23 (Mandatory put 12/01/17) (Alternative Minimum Tax)
      
   
Tax Obligation/General – 31.2%
      
1,650
  
California State, General Obligation Bonds, Various Purpose Series 2009, 5.500%, 11/01/39
11/19 at 100.00
AA–
1,897,566
1,965
  
California State, General Obligation Bonds, Various Purpose Series 2011, 5.000%, 10/01/41
10/21 at 100.00
AA–
2,176,827
2,000
  
California State, General Obligation Bonds, Various Purpose Series 2012, 5.250%, 4/01/35
4/22 at 100.00
AA–
2,275,760
   
Golden West Schools Financing Authority, California, General Obligation Revenue Refunding
      
   
Bonds, School District Program, Series 1999A:
      
4,650
  
0.000%, 8/01/16 – NPFG Insured
No Opt. Call
AA–
4,579,692
1,750
  
0.000%, 2/01/17 – NPFG Insured
No Opt. Call
AA–
1,685,705
2,375
  
0.000%, 8/01/17 – NPFG Insured
No Opt. Call
AA–
2,256,345
2,345
  
0.000%, 2/01/18 – NPFG Insured
No Opt. Call
AA–
2,188,119
   
Mountain View-Los Altos Union High School District, Santa Clara County, California, General
      
   
Obligation Capital Appreciation Bonds, Series 1995C:
      
1,015
  
0.000%, 5/01/17 – NPFG Insured
No Opt. Call
Aa1
997,166
1,080
  
0.000%, 5/01/18 – NPFG Insured
No Opt. Call
Aa1
1,017,932
   
Palomar Pomerado Health, California, General Obligation Bonds, Convertible Capital
      
   
Appreciation, Election 2004 Series 2010A:
      
10,825
  
0.000%, 8/01/34
No Opt. Call
A+
4,373,733
3,250
  
0.000%, 8/01/35
No Opt. Call
A+
1,247,415
8,075
  
San Bernardino Community College District, California, General Obligation Bonds, Election of
No Opt. Call
Aa2
2,105,718
   
2008 Series 2009B, 0.000%, 8/01/44
      
4,250
  
West Hills Community College District, California, General Obligation Bonds, School Facilities
8/31 at 100.00
AA
2,860,930
   
Improvement District 3, 2008 Election Series 2011, 0.000%, 8/01/38 – AGM Insured
      
45,230
  
Total Tax Obligation/General
    
29,662,908
   
Tax Obligation/Limited – 21.3%
      
1,000
  
Bell Community Redevelopment Agency, California, Tax Allocation Bonds, Bell Project Area,
9/15 at 100.00
AA
999,940
   
Series 2003, 5.625%, 10/01/33 – RAAI Insured
      
2,000
  
California State Public Works Board, Lease Revenue Bonds, Department of Corrections &
9/23 at 100.00
A+
2,315,960
   
Rehabilitation, Various Correctional Facilities Series 2013F, 5.250%, 9/01/33
      
1,500
  
California State Public Works Board, Lease Revenue Bonds, Various Capital Projects, Series
11/19 at 100.00
A+
1,805,940
   
2009-I, 6.375%, 11/01/34
      
120
  
Capistrano Unified School District, Orange County, California, Special Tax Bonds, Community
9/15 at 100.00
AA–
120,823
   
Facilities District 98-2, Series 2005, 5.000%, 9/01/24 – FGIC Insured
      
360
  
Chino Redevelopment Agency, California, Merged Chino Redevelopment Project Area Tax
9/16 at 101.00
A
366,865
   
Allocation Bonds, Series 2006, 5.000%, 9/01/38 – AMBAC Insured
      
1,000
  
Fontana Public Financing Authority, California, Tax Allocation Revenue Bonds, North Fontana
10/15 at 100.00
A
1,003,730
   
Redevelopment Project, Series 2005A, 5.000%, 10/01/32 – AMBAC Insured
      
270
  
Fontana Redevelopment Agency, San Bernardino County, California, Tax Allocation Bonds, Jurupa
10/15 at 100.00
A–
271,793
   
Hills Redevelopment Project, Refunding Series 1997A, 5.500%, 10/01/27
      
3,000
  
Golden State Tobacco Securitization Corporation, California, Enhanced Tobacco Settlement
6/25 at 100.00
A1
3,284,730
   
Asset-Backed Revenue Bonds, Series 2015A, 5.000%, 6/01/40
      
250
  
Inglewood Redevelopment Agency, California, Tax Allocation Bonds, Merged Redevelopment
5/17 at 100.00
BBB+
257,895
   
Project, Subordinate Lien Series 2007A-1, 5.000%, 5/01/23 – AMBAC Insured
      
   
Irvine Unified School District, California, Special Tax Bonds, Community Facilities District
      
   
Series 2006A:
      
55
  
5.000%, 9/01/26
9/16 at 100.00
N/R
55,782
130
  
5.125%, 9/01/36
9/16 at 100.00
N/R
131,760
1,215
  
Los Angeles Community Redevelopment Agency, California, Lease Revenue Bonds, Manchester
9/15 at 100.00
A1
1,218,706
   
Social Services Project, Series 2005, 5.000%, 9/01/37 – AMBAC Insured
      
135
  
National City Community Development Commission, California, Tax Allocation Bonds, National
8/21 at 100.00
A–
167,846
   
City Redevelopment Project, Series 2011, 6.500%, 8/01/24
      
1,000
  
Norco Redevelopment Agency, California, Tax Allocation Bonds, Project Area 1, Series 2009,
3/18 at 100.00
A+
1,128,440
   
7.000%, 3/01/34
      
50
  
Novato Redevelopment Agency, California, Tax Allocation Bonds, Hamilton Field Redevelopment
9/21 at 100.00
BBB+
60,122
   
Project, Series 2011, 6.750%, 9/01/40
      
60
  
Patterson Public Finance Authority, California, Revenue Bonds, Community Facilities District 2001-1,
9/23 at 100.00
N/R
63,847
   
Subordinate Lien Series 2013B , 5.875%, 9/01/39
      
   
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
370,209
320
  
5.750%, 9/01/39
9/23 at 100.00
N/R
342,851
415
  
Pittsburg Redevelopment Agency, California, Tax Allocation Bonds, Los Medanos Community
9/18 at 100.00
BBB–
452,931
   
Development Project, Refunding Series 2008A, 6.500%, 9/01/28
      
160
  
Rancho Santa Fe CSD Financing Authority, California, Revenue Bonds, Superior Lien Series
9/21 at 100.00
BBB+
180,379
   
2011A, 5.750%, 9/01/30
      
30
  
Riverside County Redevelopment Agency, California, Tax Allocation Bonds, Jurupa Valley Project
10/21 at 100.00
A–
36,740
   
Area, Series 2011B, 6.500%, 10/01/25
      
605
  
Sacramento City Financing Authority, California, Lease Revenue Refunding Bonds, Series 1993A,
No Opt. Call
AA–
665,954
   
5.400%, 11/01/20 – NPFG Insured
      
1,365
  
San Diego County Regional Transportation Commission, California, Sales Tax Revenue Bonds,
4/22 at 100.00
AAA
1,507,847
   
Series 2012A, 5.000%, 4/01/42
      
65
  
San Francisco City and County Redevelopment Agency Successor Agency, California, Special Tax
No Opt. Call
N/R
67,815
   
Bonds, Community Facilities District 7, Hunters Point Shipyard Phase One Improvements,
      
   
Refunding Series 2014, 5.000%, 8/01/39
      
25
  
San Francisco Redevelopment Finance Authority, California, Tax Allocation Revenue Bonds,
2/21 at 100.00
A–
30,151
   
Mission Bay North Redevelopment Project, Series 2011C, 6.750%, 8/01/41
      
   
San Francisco Redevelopment Financing Authority, California, Tax Allocation Revenue Bonds,
      
   
Mission Bay South Redevelopment Project, Series 2011D:
      
25
  
7.000%, 8/01/33
2/21 at 100.00
BBB+
29,999
30
  
7.000%, 8/01/41
2/21 at 100.00
BBB+
35,999
615
  
San Jose Redevelopment Agency, California, Tax Allocation Bonds, Merged Area Redevelopment
8/17 at 100.00
AA–
660,252
   
Project, Series 2006C, 5.000%, 8/01/25 – NPFG Insured
      
1,000
  
Santa Clara County Board of Education, California, Certificates of Participation, Series 2002,
10/15 at 100.00
AA–
1,000,780
   
5.000%, 4/01/25 – NPFG Insured
      
40
  
Signal Hill Redevelopment Agency, California, Project 1 Tax Allocation Bonds, Series 2011,
4/21 at 100.00
N/R
44,592
   
7.000%, 10/01/26
      
1,000
  
Travis Unified School District, Solano County, California, Certificates of Participation,
9/16 at 100.00
A3
1,045,000
   
Series 2006, 5.000%, 9/01/26 – FGIC Insured
      
360
  
Turlock Public Financing Authority, California, Tax Allocation Revenue Bonds, Series 2011,
3/21 at 100.00
A–
449,154
   
7.500%, 9/01/39
      
70
  
Yorba Linda Redevelopment Agency, Orange County, California, Tax Allocation Revenue Bonds,
9/21 at 100.00
A–
84,636
   
Yorba Linda Redevelopment Project, Subordinate Lien Series 2011A, 6.500%, 9/01/32
      
18,620
  
Total Tax Obligation/Limited
    
20,259,468
   
Transportation – 5.8%
      
530
  
Foothill/Eastern Transportation Corridor Agency, California, Toll Road Revenue Bonds,
1/24 at 100.00
BB+
626,322
   
Refunding Junior Lien Series 2013C, 6.500%, 1/15/43
      
   
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
1,089,480
1,170
  
5.750%, 1/15/46
1/24 at 100.00
BBB–
1,347,044
1,175
  
6.000%, 1/15/53
1/24 at 100.00
BBB–
1,364,809
955
  
Port of Oakland, California, Revenue Bonds, Refunding Series 2012P, 5.000%, 5/01/31
No Opt. Call
A+
1,053,594
   
(Alternative Minimum Tax)
      
4,830
  
Total Transportation
    
5,481,249
   
U.S. Guaranteed – 12.6% (4)
      
1,690
  
California State Public Works Board, Lease Revenue Bonds, Department of Corrections,
No Opt. Call
AA– (4)
1,805,934
   
Calipatria State Prison, Series 1991A, 6.500%, 9/01/17 – NPFG Insured (ETM)
      
35
  
California Educational Facilities Authority, Revenue Bonds, University of the Pacific, Series
11/15 at 100.00
A2 (4)
35,571
   
2006, 5.000%, 11/01/21 (Pre-refunded 11/02/15)
      
150
  
Healdsburg Public Financing Authority, California, Wastewater Revenue Bonds, Series 2006,
4/16 at 100.00
AA (4)
155,331
   
5.000%, 4/01/36 (Pre-refunded 4/01/16) – NPFG Insured
      
540
  
Loma Linda, California, Hospital Revenue Bonds, Loma Linda University Medical Center, Series
12/17 at 100.00
BBB– (4)
635,575
   
2008A, 8.250%, 12/01/38 (Pre-refunded 12/01/17)
      
7,600
  
Merced Irrigation District, California, Certificates of Participation, Water and Hydroelectric
9/16 at 64.56
A (4)
4,877,452
   
Series 2008B, 0.000%, 9/01/23 (Pre-refunded 9/01/16)
      
215
  
Merced Irrigation District, California, Electric System Revenue Bonds, Series 2005, 5.125%,
9/15 at 100.00
N/R (4)
216,797
   
9/01/31 (Pre-refunded 9/01/15) – SYNCORA GTY Insured
      
100
  
Roseville Joint Union High School District, Placer County, California, General Obligation
8/15 at 100.00
AA (4)
100,414
   
Bonds, Series 2006B, 5.000%, 8/01/27 (Pre-refunded 8/01/15) – FGIC Insured
      
250
  
Sacramento County Sanitation Districts Financing Authority, California, Revenue Bonds, Series
6/16 at 100.00
AA (4)
260,858
   
2006, 5.000%, 12/01/31 (Pre-refunded 6/01/16) – FGIC Insured
      
225
  
San Mateo Union High School District, San Mateo County, California, Certificates of
12/17 at 100.00
N/R (4)
247,736
   
Participation, Phase 1, Series 2007A, 5.000%, 12/15/30 (Pre-refunded 12/15/17) –
      
   
AMBAC Insured
      
1,000
  
Santa Clara Valley Transportation Authority, California, Sales Tax Revenue Bonds, Series
4/17 at 100.00
AA+ (4)
1,076,600
   
2007A, 5.000%, 4/01/36 (Pre-refunded 4/01/17) – AMBAC Insured
      
2,565
  
Sunnyvale School District, Santa Clara County, California, General Obligation Bonds, Series
9/15 at 100.00
AA+ (4)
2,586,033
   
2005A, 5.000%, 9/01/26 (Pre-refunded 9/01/15) – AGM Insured
      
14,370
  
Total U.S. Guaranteed
    
11,998,301
   
Utilities – 2.0%
      
1,000
  
Imperial Irrigation District, California, Electric System Revenue Bonds, Refunding Series
11/20 at 100.00
AA–
1,154,350
   
2011A, 5.500%, 11/01/41
      
645
  
Long Beach Bond Finance Authority, California, Natural Gas Purchase Revenue Bonds, Series
No Opt. Call
A
760,636
   
2007A, 5.500%, 11/15/37
      
1,645
  
Total Utilities
    
1,914,986
   
Water and Sewer – 7.5%
      
1,000
  
Bay Area Water Supply and Conservation Agency, California, Revenue Bonds, Capital Cost
4/23 at 100.00
AA–
1,130,000
   
Recovery Prepayment Program, Series 2013A, 5.000%, 10/01/34
      
   
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)
No Opt. Call
Baa3
395,363
1,160
  
5.000%, 11/21/45 (Alternative Minimum Tax)
No Opt. Call
Baa3
1,210,367
2,000
  
Escondido Joint Powers Financing Authority, California, Revenue Bonds, Water System Financing,
3/22 at 100.00
AA–
2,172,020
   
Series 2012, 5.000%, 9/01/41
      
1,970
  
Los Angeles Department of Water and Power, California, Waterworks Revenue Bonds, Series
7/24 at 100.00
AA
2,206,204
   
2014A, 5.000%, 7/01/44
      
6,505
  
Total Water and Sewer
    
7,113,954
$ 105,600
  
Total Long-Term Investments (cost $83,730,461)
    
91,067,702
 
Principal
    
Optional Call
    
Amount (000)
  
Description (1)
Provisions (2)
Ratings (3)
Value
   
SHORT-TERM INVESTMENTS – 0.4%
      
           
   
MUNICIPAL BONDS – 0.4%
      
           
   
Health Care – 0.4%
      
$       205
  
California Statewide Community Development Authority, Revenue Bonds, Daughters of Charity
No Opt. Call
N/R
$     205,053
   
Health System, Series 2014A, 6.000%, 7/10/15 (5)
      
100
  
California Statewide Community Development Authority, Revenue Bonds, Daughters of Charity
No Opt. Call
N/R
100,026
   
Health System, Series 2014B, 6.000%, 7/10/15 (5)
      
100
  
California Statewide Community Development Authority, Revenue Bonds, Daughters of Charity
No Opt. Call
N/R
100,026
   
Health System, Series 2014C, 6.000%, 7/10/15 (5)
      
$       405
  
Total Short-Term Investments (cost $405,000)
    
405,105
   
Total Investments (cost $84,135,461) – 96.3%
    
91,472,807
   
Other Assets Less Liabilities – 3.7%
    
3,500,773
   
Net Assets – 100%
    
$ 94,973,580
 
 
 
 
 
 
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:
        
Muicipal Bonds
$ —
$91,067,702
$        —
$91,067,702
Short-Term Investments:
        
Municipal Bonds
—
—
405,105
405,105
Total
$ —
$91,067,702
$405,105
$91,472,807
 
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, 2015, the cost of investments was $84,099,119.
 
Gross unrealized appreciation and gross unrealized depreciation of investments as of June 30, 2015, were as follows:
   
Gross unrealized:
  
Appreciation
$7,735,859
Depreciation
(362,172)
Net unrealized appreciation (depreciation) of investments
$7,373,687
 
(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)
  
Ratings: Using the highest of Standard & Poor’s Group (“Standard & Poor’s”), Moody’s Investors Service, Inc.
   
(Moody’s) or Fitch, Inc. (Fitch) rating. 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.
(5)
  
Investment valued at fair value using methods determined in good faith by, or at the discretion of, the
   
Board. For fair value measurement disclosure purposes, investment classified as Level 3.
(ETM)
  
Escrowed to maturity.
 
 
 
 
 
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/ Kevin J. McCarthy                    
                                                   Kevin J. McCarthy
                                                   Vice President and Secretary
 
Date:         August 28, 2015        
 
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/ Gifford R. Zimmerman                    
                                                    Gifford R. Zimmerman
                                                  Chief Administrative Officer (principal executive officer) 
 
Date:         August 28, 2015        
 
By (Signature and Title)     /s/ Stephen D. Foy                              
                                                   Stephen D. Foy
                                                  Vice President and Controller (principal financial officer) 
 
Date:         August 28, 2015