The Securities and Exchange Commission has not necessarily reviewed the information in this filing and has not determined if it is accurate and complete.
The reader should not assume that the information is accurate and complete.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 13F

FORM 13F INFORMATION TABLE
OMB APPROVAL
OMB Number: 3235-0006
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COLUMN 1 COLUMN 2 COLUMN 3 COLUMN 4 COLUMN 5 COLUMN 6 COLUMN 7 COLUMN 8
VALUE SHRS OR SH/ PUT/ INVESTMENT OTHER VOTING AUTHORITY
NAME OF ISSUER TITLE OF CLASS CUSIP (x$1000) PRN AMT PRN CALL DISCRETION MANAGER SOLE SHARED NONE
58.com Inc ADR COM 31680q104 138,170 3,010,896 SH   SOLE   3,010,896 0 0
Affiliated Managers Group Inc COM 008252108 2,343 16,646 SH   SOLE   16,646 0 0
Align Technology Inc. COM 016255101 3,876 48,123 SH   SOLE   48,123 0 0
Allergan PLC COM g0177j108 794 3,435 SH   SOLE   3,435 0 0
Alphabet Inc Cl A COM 02079K305 257,932 366,625 SH   SOLE   366,625 0 0
Alphabet Inc. Cl C COM 02079K107 305,689 441,683 SH   SOLE   441,683 0 0
Altria Group Inc COM 02209S103 289 4,188 SH   SOLE   4,188 0 0
American Electric Power COM 025537101 1,085 15,485 SH   SOLE   15,485 0 0
American Express COM 025816109 65,185 1,072,828 SH   SOLE   1,072,828 0 0
Apple Computer COM 037833100 489 5,110 SH   SOLE   5,110 0 0
Arch Capital Group Ltd COM g0450a105 683 9,488 SH   SOLE   9,488 0 0
AT&T Inc COM 00206r102 3,645 84,347 SH   SOLE   84,347 0 0
Athenahealth Inc. COM 04685w103 41,416 300,095 SH   SOLE   300,095 0 0
Autohome Inc ADR COM 05278c107 1,009 50,167 SH   SOLE   50,167 0 0
Automatic Data Processing COM 053015103 397 4,323 SH   SOLE   4,323 0 0
Baidu Com Inc Sponsored ADR COM 056752108 430,280 2,605,388 SH   SOLE   2,605,388 0 0
Bed Bath & Beyond Inc COM 075896100 259 6,000 SH   SOLE   6,000 0 0
Berkshire Hathaway - Cl A COM 084670108 1,499,297 6,910 SH   SOLE   6,910 0 0
Berkshire Hathaway - Cl B COM 084670702 661,903 4,571,466 SH   SOLE   4,571,466 0 0
Brown & Brown Inc. COM 115236101 439 11,722 SH   SOLE   11,722 0 0
Builders Firstsource Inc. COM 12008R107 45,083 4,007,377 SH   SOLE   4,007,377 0 0
Cabelas Inc. Cl A COM 126804301 3,776 75,421 SH   SOLE   75,421 0 0
Cable One Inc. COM 12685J105 1,651 3,228 SH   SOLE   3,228 0 0
Canadian Natural Resources COM 136385101 201 6,531 SH   SOLE   6,531 0 0
Carmax, Inc. COM 143130102 304,761 6,215,800 SH   SOLE   6,215,800 0 0
Caterpillar COM 149123101 4,960 65,432 SH   SOLE   65,432 0 0
Charter Communications Inc Del COM 16119p108 3,710 16,225 SH   SOLE   16,225 0 0
ChevronTexaco Corp COM 166764100 392 3,741 SH   SOLE   3,741 0 0
Chipotle Mexican Grill Inc COM 169656105 235,360 584,367 SH   SOLE   584,367 0 0
Coca Cola Co. COM 191216100 3,375 74,452 SH   SOLE   74,452 0 0
Colgate Palmolive Co. COM 194162103 272 3,715 SH   SOLE   3,715 0 0
Comcast Corp. Cl A COM 20030n101 485 7,445 SH   SOLE   7,445 0 0
Costco Wholesale Corp COM 22160k105 98,670 628,312 SH   SOLE   628,312 0 0
Cresud SACIFYA Spon ADR Repstg COM 226406106 8,650 612,147 SH   SOLE   612,147 0 0
CVS Corp. COM 126650100 1,422 14,856 SH   SOLE   14,856 0 0
Danaher Corp. COM 235851102 156,134 1,545,881 SH   SOLE   1,545,881 0 0
Dentsply Sirona Inc. COM 24906P109 291,914 4,705,249 SH   SOLE   4,705,249 0 0
Disney Walt COM 254687106 912 9,324 SH   SOLE   9,324 0 0
Du Pont E I De Nemours & Co. COM 263534109 208 3,208 SH   SOLE   3,208 0 0
Edison International COM 281020107 3,332 42,900 SH   SOLE   42,900 0 0
Emcor Group Inc COM 29084q100 71,195 1,445,293 SH   SOLE   1,445,293 0 0
Expeditors Int'l of Wash. Inc. COM 302130109 704 14,363 SH   SOLE   14,363 0 0
Exxon Mobil Corp COM 30231g103 5,178 55,242 SH   SOLE   55,242 0 0
Fastenal Co COM 311900104 537,160 12,100,933 SH   SOLE   12,100,933 0 0
Federal Home Loan Mortgage Cor COM 313400301 2,775 1,500,000 SH   SOLE   1,500,000 0 0
Federal National Mortgage Assn COM 313586109 3,304 1,651,820 SH   SOLE   1,651,820 0 0
General Electric COM 369604103 4,077 129,498 SH   SOLE   129,498 0 0
Goldman Sachs Group Inc COM 38141g104 83,969 565,140 SH   SOLE   565,140 0 0
Graham Holdings Co. COM 384637104 1,580 3,228 SH   SOLE   3,228 0 0
HDFC Bank Ltd ADR Repstg 3 Shs COM 40415f101 1,035 15,592 SH   SOLE   15,592 0 0
Home Depot COM 437076102 2,968 23,244 SH   SOLE   23,244 0 0
IAC Interactivecorp COM 44919P508 67,852 1,205,190 SH   SOLE   1,205,190 0 0
IBM COM 459200101 2,232 14,707 SH   SOLE   14,707 0 0
Idexx Laboratories Corp. COM 45168D104 10,019 107,894 SH   SOLE   107,894 0 0
Ingredion Inc. COM 457187102 233 1,800 SH   SOLE   1,800 0 0
Interactive Brokers Group Inc COM 45841n107 35,468 1,001,923 SH   SOLE   1,001,923 0 0
Jacobs Engineering Group Inc COM 469814107 257,761 5,174,881 SH   SOLE   5,174,881 0 0
JD.com COM 47215P106 165,917 7,815,227 SH   SOLE   7,815,227 0 0
Johnson & Johnson COM 478160104 1,569 12,933 SH   SOLE   12,933 0 0
JP Morgan Chase & Co. COM 46625h100 62,814 1,010,846 SH   SOLE   1,010,846 0 0
Lennox International Inc. COM 526107107 1,551 10,878 SH   SOLE   10,878 0 0
Liberty Global PLC Shrs CL A COM g5480u104 4,725 162,598 SH   SOLE   162,598 0 0
LKQ Corp. COM 501889208 5,135 162,000 SH   SOLE   162,000 0 0
Lockheed Martin Corp. COM 539830109 468 1,885 SH   SOLE   1,885 0 0
Makemytrip Ltd COM v5633w109 41,813 2,813,802 SH   SOLE   2,813,802 0 0
Mastercard Inc COM 57636q104 438,533 4,979,934 SH   SOLE   4,979,934 0 0
Match Group Inc. COM 57665r106 10,568 701,000 SH   SOLE   701,000 0 0
McDonalds COM 580135101 1,739 14,452 SH   SOLE   14,452 0 0
Medtronic PLC COM G5960L103 295 3,395 SH   SOLE   3,395 0 0
Merck & Co. COM 58933y105 229 3,981 SH   SOLE   3,981 0 0
Microsoft COM 594918104 1,754 34,279 SH   SOLE   34,279 0 0
Mohawk Industries COM 608190104 465,236 2,451,706 SH   SOLE   2,451,706 0 0
Monsanto Co COM 61166w101 547 5,286 SH   SOLE   5,286 0 0
Novo Nordisk A/S ADR COM 670100205 5,064 94,165 SH   SOLE   94,165 0 0
O Reilly Automotive Inc COM 67103h107 513,932 1,895,730 SH   SOLE   1,895,730 0 0
Och Ziff Capital Management Gr COM 67551U105 2,970 781,620 SH   SOLE   781,620 0 0
Omnicom Group COM 681919106 193,784 2,378,012 SH   SOLE   2,378,012 0 0
PepsiCo COM 713448108 4,498 42,462 SH   SOLE   42,462 0 0
Perrigo Co PLC COM G97822103 119,304 1,315,805 SH   SOLE   1,315,805 0 0
Pfizer COM 717081103 209 5,930 SH   SOLE   5,930 0 0
Philip Morris Intl Inc. COM 718172109 649 6,385 SH   SOLE   6,385 0 0
Pioneer Natural Resources Co. COM 723787107 258 1,708 SH   SOLE   1,708 0 0
Praxair COM 74005P104 180,490 1,605,924 SH   SOLE   1,605,924 0 0
Primerica Inc COM 74164M108 216,415 3,780,842 SH   SOLE   3,780,842 0 0
Procter & Gamble COM 742718109 8,030 94,842 SH   SOLE   94,842 0 0
Progressive Corp. Ohio COM 743315103 1,303 38,902 SH   SOLE   38,902 0 0
Public Storage Inc. COM 74460d109 637 2,492 SH   SOLE   2,492 0 0
Range Resources Corp COM 75281a109 276 6,387 SH   SOLE   6,387 0 0
Roper Industries Inc New COM 776696106 223 1,305 SH   SOLE   1,305 0 0
Royal Dutch Shell PLC Spon ADR COM 780259206 201 3,649 SH   SOLE   3,649 0 0
Ryanair Holdings PLC ADR COM 783513104 377 5,421 SH   SOLE   5,421 0 0
Schlumberger Ltd COM 806857108 2,678 33,861 SH   SOLE   33,861 0 0
Schwab Charles Corp COM 808513105 231,722 9,155,367 SH   SOLE   9,155,367 0 0
Sherwin Williams Co. COM 824348106 504 1,717 SH   SOLE   1,717 0 0
Signet Jewelers Limited COM G81276100 251 3,046 SH   SOLE   3,046 0 0
Soufun Holdings LTD ADR COM 836034108 5,072 1,008,260 SH   SOLE   1,008,260 0 0
Third Point Reinsurance LTD COM g8827u100 35,502 3,029,190 SH   SOLE   3,029,190 0 0
Tiffany & Co COM 886547108 120,651 1,989,625 SH   SOLE   1,989,625 0 0
Time Warner Inc COM 887317303 9,289 126,308 SH   SOLE   126,308 0 0
TJX Cos - New COM 872540109 940,948 12,183,709 SH   SOLE   12,183,709 0 0
Trimble Navigation Ltd. COM 896239100 67,742 2,780,872 SH   SOLE   2,780,872 0 0
U.S. Bancorp New - Del. COM 902973304 770 19,089 SH   SOLE   19,089 0 0
Union Pacific COM 907818108 5,412 62,026 SH   SOLE   62,026 0 0
Valeant Pharmaceuticals Intern COM 91911k102 8,991 446,442 SH   SOLE   446,442 0 0
Verisk Analytics Class A COM 92345Y106 4,482 55,281 SH   SOLE   55,281 0 0
Vipshop Hldgs Ltd ADR COM 92763w103 11,454 1,025,460 SH   SOLE   1,025,460 0 0
Visa Inc Class A COM 92826C839 188,211 2,537,564 SH   SOLE   2,537,564 0 0
Wal-Mart Stores COM 931142103 121,660 1,666,115 SH   SOLE   1,666,115 0 0
Waters Corp COM 941848103 248,952 1,770,014 SH   SOLE   1,770,014 0 0
Wayfair Inc Cl A COM 94419L101 4,961 127,200 SH   SOLE   127,200 0 0
Wells Fargo & Co. New COM 949746101 248,132 5,242,602 SH   SOLE   5,242,602 0 0
West Pharmaceutical Svcs Inc C COM 955306105 33,616 443,019 SH   SOLE   443,019 0 0
Woodward Inc COM 980745103 600 10,401 SH   SOLE   10,401 0 0
WPP PLC New ADR COM 92937a102 267 2,556 SH   SOLE   2,556 0 0
Yandex NV Shs COM n97284108 59,068 2,703,355 SH   SOLE   2,703,355 0 0
Yelp Inc. COM 985817105 229 7,535 SH   SOLE   7,535 0 0
JP Morgan Chase & Co Exp 10/28 WAR 46634e114 28,350 1,400,000 SH   SOLE   1,400,000 0 0