N-Q 1 c42459_n-q.htm
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM N-Q

QUARTERLY SCHEDULE OF PORTFOLIO HOLDINGS OF REGISTERED
MANAGEMENT INVESTMENT COMPANY

Investment Company Act file number:__811-21280______

_______BlackRock Preferred Opportunity Trust_______
(Exact name of registrant as specified in charter)

100 Bellevue Parkway, Wilmington, DE 
19809 
(Address of principal executive offices) 
(Zip code) 

Robert S. Kapito, President
BlackRock Preferred Opportunity Trust
40 East 52nd Street, New York, NY 10022
(Name and address of agent for service)

Registrant's telephone number, including area code:_888-825-2257                              

Date of fiscal year end:___December 31, 2006
Date of reporting period:__March 31, 2006

Item 1. Schedule of Investments.
The Registrant’s unaudited schedule of investments as of the close of the reporting period pursuant to Rule 30b1-5 under the Investment Company Act of 1940 is as follows:

PORTFOLIO OF INVESTMENTS
MARCH 31, 2006 (unaudited)
BlackRock Preferred Opportunity Trust (BPP)
       
         
Rating1 Shares   Description Value  
    LONG-TERM INVESTMENTS—146.8%  
      Preferred Securities—59.3%  
      Consumer Products—0.4%  
BBB- 20,000 2 Dairy Farmers of America, Inc., 7.875% $      1,970,626  
      Energy—3.0%  
BB+ 5,000   Devon Energy Corp., Ser. A, 6.49% 505,156  
B- 115,000   Hanover Compressor Capital Trust, 7.25% 5,948,375  
Baa3 275,000   Nexen, Inc., 7.35% (Canada) 7,128,000  
        13,581,531  
      Financial Institutions—40.3%  
A3 600   ABN Amro NA, Inc., 6.46% 606,750  
Baa2 300,000   ACE Ltd., Sec. C, 7.80% (Cayman Islands) 7,856,250  
A3 47,000 3  Aegon NV, Ser. 1, 5.785% (Netherlands) 1,203,200  
BBB- 340,000   Arch Capital Group Ltd., 8.00% (Bermuda) 8,659,392  
      Axis Capital Holdings Ltd. (Bermuda)  
BBB- 217,000        Ser. A, 7.25% 5,296,970  
BBB- 32,000        Ser. B, 7.50% 3,219,002  
A2 30,000   Banesto Holdings Ltd., Ser. A, 10.50% 915,939  
A 100,000   Bear Stearns Co., Inc., Ser. E, 6.15% 5,009,380  
BB 60,000   Chevy Chase Preferred Capital Corp., Ser. A, 10.375% 3,202,500  
A- 80,000   CIT Group, Inc., 6.35% 2,016,000  
A3 23,600   Citigroup Capital I, 6.75% 589,764  
AA 40,000   Citigroup Capital X, 6.10% 965,200  
AA 50,000   Citigroup Capital XI, 6.00% 1,191,500  
BB 80,000   Colonial Capital Trust IV, 7.875% 2,044,000  
      Credit Suisse First Boston, Inc.,  
Aa3 11,100        6.25% 270,285  
Aa3 12,300        7.00% 313,650  
Baa3 300,000   Endurance Specialty Holdings Ltd., 7.75% (Bermuda) 7,266,000  
A- 72,500   Everest Re Capital Trust, 7.85% 1,857,812  
A- 30,000   Everest Re Capital Trust II, Ser. B, 6.20% 670,500  
AA 15,200   Financial Security Assurance Holdings Ltd., 5.60% 350,664  
      First Republic Bank,  
BBB- 185,000        6.25% 4,717,500  
BBB- 277,200        6.70% 7,016,625  
BBB- 120,000   First Republic Preferred Capital Corp., 7.25% 2,988,000  
Aa3 85,000   Fleet Capital Trust VII, 7.20% 2,135,200  
Aa3 26,100   Fleet Capital Trust VIII, 7.20% 659,808  
      Goldman Sachs Group, Inc.,  
Aa3 102,900        6.00% 2,398,856  
A+ 200,000        Ser. B, 6.20% 5,128,000  
AA- 200,000   HSBC Holdings PLC, 6.20%, 12/31/49 (United Kingdom) 4,892,000  
A 76,700   ING Groep NV, 7.05% (Netherlands) 1,941,469  
A1 80,000   J.P. Morgan Chase Capital XII, 6.25% 2,010,000  
A3 117,200   KeyCorp Capital V, 5.875% 2,746,875  
A 113,400   Lehman Brothers Holdings Capital Trust III, Ser. K, 6.375% 2,813,737  
A 90,000   Lehman Brothers Holdings Capital Trust IV, Ser. L, 6.375% 2,236,500  
A 31,100   Lehman Brothers Holdings, Inc., Ser. D, 5.67% 1,545,281  
A+ 20,000   Merrill Lynch Preferred Capital Trust III, 7.00% 508,126  
A+ 86,900   Merrill Lynch Preferred Capital Trust V, 7.28% 2,228,985  
A- 425,000   MetLife, Inc., Ser. B, 6.50% 10,871,500  
Aa3 1,300   Morgan Stanley, 7.05%, 4/01/32 32,581  
A+ 187,000   Morgan Stanley Capital Trust III, 6.25% 4,555,320  
BBB 7,200   News Corp. Ltd., Ser. 9, Class 1, 8.125% 185,760  
A 209,400   PartnerRe Ltd., Ser. C, 6.75% (Bermuda) 5,202,292  
BBB 79,385   Phoenix Cos., Inc., 7.45% 1,985,419  
BBB+ 18,400   PLC Capital Trust IV, 7.25% 466,326  
A- 109,975   Principal Financial Group, 6.518% 2,969,325  
      RenaissanceRe Holdings Ltd. (Bermuda)  
BBB 271,725        Ser. B, 7.30% 6,886,544  
BBB 100,000        Ser. C, 6.08% 2,150,000  
BBB- 30   Roslyn Real Estate Asset Corp., Ser. C, 8.95% 3,168,750  
AA- 375,000   Royal Bank of Scotland Group PLC ADR, 6.35% (United Kingdom) 9,442,500

1

BlackRock Preferred Opportunity Trust (BPP) (continued)

       
         
Rating1 Shares   Description Value  
    Financial Institutions—(cont’d)  
      Safeco Capital Trust I,  
Baa2 4,100        8.072% (CORTS) $        106,600  
Baa2 23,600        8.25% (SATURNS) 611,791  
Baa2 2,000        8.375% (CORTS) 52,040  
Baa2 14,700        8.70% (CORTS) 402,339  
Baa2 29,200        8.75% (CORTS) 847,092  
A 5,000   SLM Corp., Ser. A, 6.97% 266,094  
A- 50,600   Sprint Corp., 7.00% 1,270,060  
A- 103,439   Structured Repackaged Asset-Backed Trust Securities, 6.50% 2,504,258  
A 60 2  Union Planters Preferred Funding Corp., 7.75% 6,802,920  
Aa3 150,000   USB Capital VII, 5.875% 3,456,000  
BBB- 11,100   Valero Energy Corp., 7.25% 287,046  
A2 404,400   Wachovia Preferred Funding Corp., Ser. A, 7.25% 11,070,450  
Baa1 5,200   Washington Mutual Capital I, 7.65% 133,575  
Baa1 143,865   Zions Capital Trust, 8.00% 3,771,968  
Baa2 2,000 2  Zurich Regcaps Funding Trust, 6.58% 2,069,375  
        181,039,645  
      Media—2.6%  
BBB+ 253,100   AOL Time Warner, Inc., Ser. A-1, 7.625% 6,598,317  
BBB 110   Comcast Corp., 2.00%, 11/15/29 5,034,150  
        11,632,467  
      Real Estate—13.0%  
      BRE Properties,  
BBB- 225,000        Ser. C, 6.75% 5,537,250  
BBB- 80,000        Ser. D, 6.75% 1,957,504  
BBB- 238,888   CarrAmerica Realty Corp., Ser. E, 7.50% 6,015,200  
BBB- 120,000   Developers Diversified Realty Corp., 7.375% 2,988,756  
      Duke Realty Corp.,  
BBB 90,000        Ser. J, 6.625% 2,223,900  
BBB 160,800        Ser. K, 6.50% 3,964,733  
BBB 100,000        Ser. M, 6.95% 2,580,000  
BBB+ 172,000   Kimco Realty Corp., Ser. F, 6.65% 4,283,884  
BBB+ 255,200   NB Capital Corp., 8.35% 6,737,280  
      Regency Centers Corp.,  
BBB 75,000        6.70% 1,856,250  
BBB 324,000        7.45% 8,312,641  
Aa3 30 2  Sun Trust Real Estate Investment Corp., 9.00% 4,016,250  
A- 320,000   Weingarten Realty Investors, Ser. D, 6.75% 8,128,000  
        58,601,648  
      Total Preferred Securities 266,825,917  
 
Principal
     
 
Amount
     
 
(000)
     
      Trust Preferred Securities—34.0%  
      Energy—1.8%  
BB+ $ 3,000   HL&P Capital Trust II, 8.257%, 2/01/37 3,052,500  
BBB- 4,655   KN Capital Trust III, 7.63%, 4/15/28 4,964,325  
        8,016,825  
      Financial Institutions—29.5%  
BB+ 4,500   AFC Capital Trust I, 8.207%, 2/03/27 4,661,744  
A2 6,000 2  AgFirst Farm Credit Bank, 7.30%, 10/14/49 6,084,000  
A3 9,774   AXA SA, 7.10%, 5/29/49 (France) 9,826,734  
A+ 3,557   BNP Paribas Capital Trust V, 7.20%, 12/31/49 3,592,570  
BBB- 1,100   Colonial Capital Trust II, 8.92%, 1/15/27 1,168,996  
A1 3,000   Credit Agricole Preferred Fund Trust II, 7.00%, 8/29/49 3,030,000  
A+ 14,500 2  Deutsche Bank Capital Funding Trust I, 7.872%, 12/29/49 15,378,990  
A+ 5,000 2  Deutsche Bank Capital Funding Trust VII, 5.628%, 1/19/49 4,843,500  
A- 8,000 2  Dresdner Funding Trust I, 8.151%, 6/30/31 9,399,246  
Baa2 1,100   FCB/NC Capital Trust I, 8.05%, 3/01/28 1,172,479  
BBB- 5,000   Greenpoint Capital Trust I, 9.10%, 6/01/27 5,389,726  
A1 5,000   HBOS Capital Funding LP, 6.85%, 3/29/49 5,012,500  
A- 1,400   HUBCO Capital Trust I, 8.98%, 2/01/27 1,514,780  
A- 3,000   HUBCO Capital Trust II, 7.65%, 6/15/28 3,223,500  
A1 1,000   JPM Capital Trust II, 7.95%, 2/01/27 1,055,971

2

BlackRock Preferred Opportunity Trust (BPP) (continued)

Principal      
  Amount      
Rating1 (000)   Description Value  
    Financial Institutions—(cont’d)  
A $12,700 2,3 Lehman Brothers Holdings E-Capital Trust I, 5.55%, 8/19/65 $   12,678,410  
BBB+ 10,000 2  Mangrove Bay Pass-Through Trust, 6.102%, 7/15/33 9,658,700  
BB+ 3,145   Markel Capital Trust I, 8.71%, 1/01/46 3,313,586  
A 2,000   NBP Capital Trust III, 7.375%, 10/29/49 2,065,008  
BBB- 3,000   North Fork Capital Trust II, 8.00%, 12/15/27 3,206,096  
BBB+ 5,000   Old Mutual Capital Funding, 8.00%, 5/29/49 (United Kingdom) 5,212,500  
A1 3,000   RBS Capital Trust, 6.80%, 12/31/49 3,008,317  
A+ 4,600 2  State Street Institutional Capital A, 7.94%, 12/30/26 4,843,274  
A+ 7,500 2  Sun Life of Canada U.S. Capital Trust I, 8.526%, 5/29/49 8,012,550  
BB+ 5,000 2  Webster Capital Trust I, 9.36%, 1/29/27 5,341,807  
        132,694,984  
      Real Estate—2.7%  
BB+ 8,180 2  Sovereign Real Estate Investor Corp., 12.00%, 8/29/49 11,942,800  
      Total Trust Preferred Securities 152,654,609  
      Corporate Bonds—52.0%  
      Aerospace & Defense—0.4%  
B- 1,770   DI Finance/DynCorp. Intl., 9.50%, 2/15/13 1,840,800  
      Automotive—0.9%  
BB+ 25   ArvinMeritor, Inc., 8.75%, 3/01/12 24,875  
B- 30   Goodyear Tire & Rubber Co., 7.857%, 8/15/11 29,400  
B+ 440   Lear Corp., 5.75%, 8/01/14 355,300  
CCC+ 250   Metaldyne Corp., 10.00%, 11/01/13 233,750  
B3 2,850   Rexnord Corp., 10.125%, 12/15/12 3,127,875  
B 120   Tenneco, Inc., 8.625%, 11/15/14 120,000  
        3,891,200  
      Basic Materials—1.6%  
B+ 120   Abitibi-Consolidated Co., 8.375%, 4/01/15 (Canada) 117,600  
B- 100 2,3 BCI US Finance Corp./Borden 2 Nova Scotia Finance ULC, 10.568%, 7/15/10 102,000  
B- 2,145   Caraustar Industries, Inc., 9.875%, 4/01/11 2,257,612  
B+ 200   Donohue Forest Products, 7.625%, 5/15/07 (Canada) 202,750  
B2 220 3  Huntsman LLC, 12.318%, 7/15/11 231,550  
B- 600 2  Ineos Group Holdings PLC, 8.50%, 2/15/16 (United Kingdom) 570,000  
      Lyondell Chemical Co.,   
BB+ 2,235        11.125%, 7/15/12 2,458,500  
BB+ 465        Ser. A, 9.625%, 5/01/07 480,113  
B3 450   NewPage Corp., 10.00%, 5/01/12 474,750  
BB+ 340 3  Nova Chemicals Corp., 7.561%, 11/15/13 (Canada) 340,000  
        7,234,875  
      Building & Development—1.0%  
B2 260 2  Compression Polymers Corp., 10.50%, 7/01/13 265,200  
B- 300   ERICO Intl. Corp., 8.875%, 3/01/12 309,000  
B- 695   Goodman Global Holding Co., Inc., 7.875%, 12/15/12 686,312  
BB+ 3,250   K Hovnanian Enterprises, Inc., 6.25%, 1/15/15 2,981,875  
B 170   North American Energy Partners, Inc., 9.00%, 6/01/10 (Canada) 180,200  
        4,422,587  
      Consumer Products—1.5%  
B3 115   ALH Finance LLC, 8.50%, 1/15/13 112,988  
B+ 3,000   Cenveo Corp., 9.625%, 3/15/12 3,225,000  
B- 145   Finlay Fine Jewelry Corp., 8.375%, 6/01/12 127,237  
B 110   Gold Kist, Inc., 10.25%, 3/15/14 118,800  
B- 140 2  Knowledge Learning Corp., Inc., 7.75%, 2/01/15 133,000  
B- 1,260   Lazydays RV Center, Inc., 11.75%, 5/15/12 1,244,250  
B 460 3  Levi Strauss & Co., 9.74%, 4/01/12 476,100  
CCC- 335   Movie Gallery, Inc., 11.00%, 5/01/12 165,825  
BB- 300   Quiksilver, Inc., 6.875%, 4/15/15 285,750  
B- 750 2  Rite Aid Corp., 6.125%, 12/15/08 723,750  
        6,612,700  
      Containers & Packaging—0.2%  
B1 385 2  Crown Americas LLC/Crown Americas Capital Corp., 7.75%, 11/15/15 399,438  
B+ 330   Smurfit-Stone Container Enterprises, Inc., 9.75%, 2/01/11 339,900  
        739,338  

3

BlackRock Preferred Opportunity Trust (BPP) (continued)

Principal      
  Amount      
Rating1 (000)   Description Value  
    Ecological Services & Equipment—0.1%  
BB- $      290   Allied Waste NA, Inc., 5.75%, 2/15/11 $        274,775  
      Energy—3.2%  
BB 3,000   AES Corp., 8.875%, 2/15/11 3,240,000  
B2 235   Aquila Finance Corp., 7.75%, 6/15/11 (Canada) 242,050  
B 220 2  Chaparral Energy, Inc., 8.50%, 12/01/15 228,250  
BB 30 2  Chesapeake Energy Corp., 6.875%, 11/15/20 30,450  
B- 285   Clayton Williams Energy, Inc., 7.75%, 8/01/13 266,475  
BB- 85   CMS Energy Corp., 8.50%, 4/15/11 92,225  
BB- 210   Compagnie Generale de Geophysique SA, 7.50%, 5/15/15 (France) 216,300  
      Compton Petroleum Finance Corp. (Canada)  
B 130        7.625%, 12/01/13 130,650  
B 220 2       7.625%, 12/01/13 221,100  
B2 710   Dresser, Inc., 9.375%, 4/15/11 743,725  
B+ 1,190 2  Dynegy Holdings, Inc., 10.125%, 7/15/13 1,359,575  
B 280 2  Hilcorp Energy I LP/Hilcorp Finance Corp., 7.75%, 11/01/15 279,300  
B+ 18   Midwest Generation LLC, 8.56%, 1/02/16 19,363  
      Mirant Americas Generation LLC,  
B 50        8.30%, 5/01/11 51,625  
B 60        9.125%, 5/01/31 64,277  
B- 130 2  Ocean Rig AS, 8.375%, 7/01/13 (Norway) 139,750  
B- 2,950   Orion Power Holdings, Inc., 12.00%, 5/01/10 3,326,125  
      Reliant Energy, Inc.,  
BB- 210        6.75%, 12/15/14 186,900  
BB- 50        9.25%, 7/15/10 50,125  
B 200   Roseton/Danskammer, 7.27%, 11/08/10 202,000  
B- 420 2  Targa Resources, Inc., 8.50%, 11/01/13 439,950  
B2 55   Whiting Petroleum Corp., 7.00%, 2/01/14 54,450  
      Williams Cos., Inc.,  
B+ 2,000        7.125%, 9/01/11 2,057,500  
B+ 505        8.75%, 3/15/32 589,587  
        14,231,752  
      Entertainment & Leisure—0.2%  
B3 435 2  Greektown Holdings LLC, 10.75%, 12/01/13 444,788  
B 130   Poster Financial Group, Inc., 8.75%, 12/01/11 136,825  
B+ 130 2  San Pasqual Casino, 8.00%, 9/15/13 131,300  
B+ 40   Wynn Las Vegas LLC/Wynn Las Vegas Capital Corp., 6.625%, 12/01/14 39,100  
        752,013  
      Financial Institutions—38.0%  
AA- 9,605 2,4 American General Institute Capital, 7.57%, 12/01/45 11,039,444  
BB 415   American Real Estate Partners LP/American Real Estate Finance Corp., 7.125%, 2/15/13 408,775  
Aa3 5,000   BAC Capital Trust V, 5.625%, 3/08/35 4,651,216  
AA 10,000 2  Barclays Bank PLC, 7.375%, 6/29/49 (United Kingdom) 10,750,800  
B 300   BCP Crystal US Holdings Corp., 9.625%, 6/15/14 332,250  
BB 1,000   Crum & Forster Holdings Corp., 10.375%, 6/15/13 1,025,000  
      E*Trade Financial Corp.,  
B+ 125        7.375%, 9/15/13 127,500  
B+ 170        7.875%, 12/01/15 180,200  
BB 4,455   Fairfax Financial Holdings Ltd., 7.75%, 4/26/12 (Canada) 4,009,500  
BBB 11,500   First Midwest Capital Trust I, 6.95%, 12/01/33 12,079,726  
BB 125   Ford Motor Credit Co., 7.25%, 10/25/11 112,373  
B- 70   Hexion US Finance Corp./Hexion Nova Scotia Finance ULC, 9.00%, 7/15/14 72,275  
AA- 7,000   HSBC Bank USA, Inc., 5.875%, 11/01/34 6,840,306  
AA- 10,000 2  HSBC Capital Funding LP, 4.61%, 12/29/49 (Jersey Channel Islands) 9,179,810  
A1 5,000   JP Morgan Chase Capital XVII, 5.85%, 8/01/35 4,647,960  
BBB- 9,000   Kingsway America, Inc., 7.50%, 2/01/14 9,116,535  
A+ 7,399   Lloyds Bank Ltd., 6.90%, 10/10/49 (United Kingdom) 7,417,497  
BBB 9,000 3  MUFG Capital Finance 1 Ltd., 6.346%, 7/29/49 (Cayman Islands) 9,000,000  
B- 540 2  Basell AF SCA, 8.375%, 8/15/15 (Luxembourg) 540,675  
NA 8,000   Prudential PLC, 6.50%, 6/29/49 (United Kingdom) 7,944,000  
AA 10,000 2  Rabobank Capital Funding II, 5.26%, 12/31/49 9,603,080  
A- 10,000   Reinsurance Group of America, Inc., 6.75%, 12/15/65 9,483,254  
A3 4,000   Resparcs Funding Ltd., 8.00%, 12/30/49 (Hong Kong) 4,130,000  
      Skandinaviska Enskilda Banken AB (Sweden)  
A 7,185 2       4.958%, 3/29/49 6,670,734  
A 5,000 2       5.471%, 3/29/49 4,733,920

4

BlackRock Preferred Opportunity Trust (BPP) (continued)

Principal      
  Amount      
Rating1 (000)   Description Value  
    Financial Institutions—(cont’d)  
Ba1 $ 2,000   Sovereign Capital Trust, 9.00%, 4/01/27 $      2,129,731  
Caa1 30   Standard Aero Holdings, Inc., 8.25%, 9/01/14 26,175  
AA+ 3,894 5  Structured Asset Receivable Trust, 1.649%, 1/21/10 3,893,628  
AA 10,000   UBS Preferred Funding Trust I, 8.622%, 10/29/49 11,157,150  
B- 60 3  Universal City Florida Holding Co. I/II, 9.43%, 5/01/10 61,200  
A+ 5,000   Wachovia Capital Trust III, 5.80%, 3/15/42 4,908,594  
Aa3 60   Western Financial Bank, 9.625%, 5/15/12 67,050  
A2 3,000 2  Westpac Capital Trust IV, 5.256%, 12/29/49 2,811,609  
      ZFS Finance USA Trust I,  
Baa2 5,000 2       6.06%, 12/15/65 5,009,500  
Baa2 7,000 2       6.45%, 12/15/65 6,790,000  
        170,951,467  
      Health Care—0.2%  
B 220 2  Angiotech Pharmaceuticals, Inc., 7.75%, 4/01/14 (Canada) 221,100  
B3 260   Select Medical Corp., 7.625%, 2/01/15 234,650  
B- 520   Universal Hospital Services, Inc., 10.125%, 11/01/11 538,200  
        993,950  
      Industrials—0.3%  
B- 75   Ahern Rentals, Inc., 9.25%, 8/15/13 78,188  
CCC+ 1,205   Trimas Corp., 9.875%, 6/15/12 1,063,412  
Caa1 225   United Rentals NA, Inc., 7.00%, 2/15/14 216,000  
        1,357,600  
      Media—1.3%  
B- 200   Allbritton Communications Co., 7.75%, 12/15/12 201,500  
B+ 230 3,6 Cablevision Systems Corp., 9.62%, 4/01/09 242,650  
BB- 350   CSC Holdings, Inc., 7.875%, 12/15/07 357,875  
B 1,950   Dex Media West LLC/Dex Media Finance Co., 9.875%, 8/15/13 2,152,312  
BB- 75 2  Echostar DBS Corp., 7.125%, 2/01/16 73,688  
B2 220 2  Network Communications, Inc., 10.75%, 12/01/13 223,850  
B3 330   Nexstar Finance, Inc., 7.00%, 1/15/14 311,850  
B2 350 2,3 Paxson Communications Corp., 8.318%, 1/15/12 352,625  
      Primedia, Inc.,  
B2 40        8.00%, 5/15/13 36,800  
B2 280 3       10.124%, 5/15/10 285,600  
BBB+ 719   TCI Communications, Inc., 7.875%, 2/15/26 785,595  
B3 650   Vertis, Inc., 9.75%, 4/01/09 666,250  
        5,690,595  
      Real Estate—1.4%  
      Rouse Co.,  
BB+ 5,000        3.625%, 3/15/09 4,641,378  
BB+ 2,000        5.375%, 11/26/13 1,872,003  
        6,513,381  
      Technology—0.4%  
B+ 210   Celestica, Inc., 7.625%, 7/01/13 (Canada) 211,838  
B+ 120 2  Hynix Semiconductor, Inc., 9.875%, 7/01/12 (South Korea) 132,300  
      MagnaChip Semiconductor SA/MagnaChip Semiconductor Finance Co. (Luxembourg)  
B2 20        8.00%, 12/15/14 18,700  
Ba3 90 3       8.16%, 12/15/11 91,125  
BB 60   STATS ChipPAC Ltd., 7.50%, 7/19/10 (Singapore) 60,975  
      Sungard Data Systems, Inc.,  
B- 115 2       9.125%, 8/15/13 121,325  
B- 375 2,3      9.431%, 8/15/13 393,750  
B- 320 2       10.25%, 8/15/15 336,800  
B 460   Superior Essex Communications LLC/Essex Group, Inc., 9.00%, 4/15/12 463,450  
B- 110   UGS Corp., 10.00%, 6/01/12 121,000  
        1,951,263  
      Telecommunications—1.0%  
BB- 290   Cincinnati Bell, Inc., 7.25%, 7/15/13 299,425  
B3 190 2,3 Hawaiian Telcom Communications, Inc., 9.948%, 5/01/13 187,150  
Caa1 200   Intelsat Ltd., 5.25%, 11/01/08 (Bermuda) 188,500  

5

BlackRock Preferred Opportunity Trust (BPP) (continued)

Principal      
  Amount      
Rating1 (000)   Description Value  
    Telecommunications—(cont’d)  
      Intelsat Subsidiary Holding Co. Ltd. (Bermuda)  
B2 $       80        8.25%, 1/15/13 $         81,400  
B2 355        8.625%, 1/15/15 367,425  
B2 365 3       9.614%, 1/15/12 373,212  
      Lucent Technologies, Inc.,  
B1 25        6.45%, 3/15/29 22,625  
B1 185        6.50%, 1/15/28 165,113  
B2 80   Nortel Networks Corp., 6.875%, 9/01/23 (Canada) 73,400  
      Qwest Corp.,  
BB+ 1,845        7.875%, 9/01/11 1,967,231  
BB+ 460 3       8.16%, 6/15/13 503,700  
B+ 420 2  Wind Acquisition Finance SA, 10.75%, 12/01/15 (Luxembourg) 452,025  
        4,681,206  
      Transportation—0.3%  
B 90   CHC Helicopter Corp., 7.375%, 5/01/14 (Canada) 91,800  
BB- 70 2  Hertz Corp., 8.875%, 1/01/14 72,800  
B3 32   Horizon Lines LLC, 9.00%, 11/01/12 33,840  
B+ 80   OMI Corp., 7.625%, 12/01/13 (Marshall Island) 81,600  
B 1,095   Sea Containers Ltd., 10.50%, 5/15/12 (Bermuda) 1,029,300  
        1,309,340  
      Total Corporate Bonds 233,448,842  
      U.S. Government and Agency Securities—1.5%  
  2,000   U.S. Treasury Bonds, 5.375%, 2/15/31 2,105,000  
  4,600   U.S. Treasury Notes, 4.50%, 2/28/11 4,532,438  
      Total U.S. Government and Agency Securities 6,637,438  
      Total Long-Term Investments (cost $655,264,930) 659,566,806  
      SHORT-TERM INVESTMENTS—1.5%  
      U.S. Government and Agency Zero Coupon Bonds—1.5%  
      Federal Home Loan Bank Discount Notes,  
  3,081 7       4.502%, 4/05/06 3,079,463  
  3,200 7       4.552%, 4/03/06 3,199,191  
  700 7  U.S. Treasury Bills, 4.359%, 4/06/06 699,578  
      Total Short-Term Investments (cost $6,978,232) 6,978,232  
      Total investments before borrowed bonds and investments sold short (cost $662,243,1618) 666,545,038  
      BORROWED BONDS—7.4%  
      U.S. Treasury Notes,  
  14,268 7       3,25%, 4/12/06 14,267,894  
  18,919 7       4.30%, 4/07/06 18,918,787  
      Total Borrowed Bonds (cost $33,186,681) 33,186,681  
      INVESTMENTS SOLD SHORT—(7.3)%  
  (33,605)   U.S. Treasury Notes, 4.50%, 11/15/15-2/15/16 (32,629,716)  
      Total investments net of borrowed bonds and investments sold short—148.4% $ 667,102,003  
      Other assets in excess of liabilities—0.7% 3,203,581  
      Preferred shares at redemption value, including dividends payable—(49.1)% (220,846,873)  
      Net Assets Applicable to Common Shareholders—100% $ 449,458,711  

1   Using the higher of Standard & Poor’s, Moody’s Investor Service or Fitch’s ratings.  
2   Security is not registered under the Securities Act of 1933. These securities may be resold in transactions in accordance with Rule 144A under that Act, to qualified institutional buyers. As of March 31, 2006, the Trust held 39.6% of its net assets, with a current market value of $178,207,284, in securities restricted as to resale.  
3   Rate shown is interest rate as of March 31, 2006.  
4   Security, or a portion thereof, pledged as collateral with a value of $2,936,441 on 338 short U.S. Treasury Bond futures contracts and 96 short U.S. Treasury Note futures contracts expiring June 2006. The notional value of such contracts on March 31, 2006 was $47,108,313, with an unrealized gain of $645,423.  
5   Illiquid Security. As of March 31, 2006, the Trust held 0.9% of its net assets, with a current market value of 3,893,628.  
6   Security is fair valued.  
7   Rate shown is the yield to maturity as of March 31, 2006.  
8   Cost for Federal income tax purposes is $662,568,219. The net unrealized appreciation on a tax basis is $3,976,819, consisting of $13,137,586 gross unrealized appreciation and $9,160,767 gross unrealized depreciation.  
9   The interest rate and maturity date shown represent the terms of the borrowed transaction, not the security borrowed.  
       
    A category in the Preferred Securities, Trust Preferred Securities and Corporate Bonds sections may contain multiple industries as defined by the SEC’s Standard Industry Codes. 

6

BlackRock Preferred Opportunity Trust (BPP) (continued)

KEY TO ABBREVIATIONS
ADR — American Depositary Receipts SATURNS — Structured Asset Trust Unit Repackagings
CORTS — Corporate Backed Trust Securities      

7

Item 2. Controls and Procedures.

(a) The Registrant's principal executive and principal financial officers have evaluated the Registrant's disclosure controls and procedures within 90 days of this filing and have concluded, as of that date, that the Registrant’s disclosure controls and procedures were reasonably designed to ensure that information required to be disclosed by the Registrant in this Form N-Q was recorded, processed, summarized, and reported within the required time periods and that information to be disclosed by the Registrant in this Form N-Q was accumulated and communicated to the Registrant’s management, including its principal executive and principal financial officers, as appropriate, to allow timely decisions regarding required disclosure.

(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.

Separate certifications of the Registrant’s Principal Executive and Financial Officers pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 are attached as EX-99.CERT.

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)___BlackRock Preferred Opportunity Trust___

By:___/s/ Henry Gabbay____________________________________
Name: Henry Gabbay
Title: Treasurer and Principal Financial Officer
Date: May 25, 2006

          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:___/s/ Robert S. Kapito___________________________________
Name: Robert S. Kapito
Title: President and Principal Executive Officer
Date: May 25, 2006

By:__/s/ Henry Gabbay______________________________________
Name: Henry Gabbay
Title: Treasurer and Principal Financial Officer
Date: May 25, 2006