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
Estimated average burden
hours per response: 23.8
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 238,887 5,012,316 SH   SOLE   5,012,316 0 0
Affiliated Managers Group Inc COM 008252108 2,409 16,646 SH   SOLE   16,646 0 0
Align Technology Inc. COM 016255101 4,512 48,123 SH   SOLE   48,123 0 0
Allergan PLC COM g0177j108 708 3,075 SH   SOLE   3,075 0 0
Alphabet Inc Cl A COM 02079K305 272,904 339,408 SH   SOLE   339,408 0 0
Alphabet Inc. Cl C COM 02079K107 341,357 439,163 SH   SOLE   439,163 0 0
American Electric Power COM 025537101 924 14,390 SH   SOLE   14,390 0 0
American Express COM 025816109 49,394 771,298 SH   SOLE   771,298 0 0
Arch Capital Group Ltd COM g0450a105 752 9,488 SH   SOLE   9,488 0 0
AT&T Inc COM 00206r102 3,323 81,830 SH   SOLE   81,830 0 0
Athenahealth Inc. COM 04685w103 37,848 300,095 SH   SOLE   300,095 0 0
Autohome Inc ADR COM 05278c107 1,217 50,167 SH   SOLE   50,167 0 0
Automatic Data Processing COM 053015103 361 4,096 SH   SOLE   4,096 0 0
Baidu Com Inc Sponsored ADR COM 056752108 481,646 2,645,388 SH   SOLE   2,645,388 0 0
Berkshire Hathaway - Cl A COM 084670108 1,292,563 5,978 SH   SOLE   5,978 0 0
Berkshire Hathaway - Cl B COM 084670702 636,573 4,406,265 SH   SOLE   4,406,265 0 0
Brown & Brown Inc. COM 115236101 352 9,322 SH   SOLE   9,322 0 0
Builders Firstsource Inc. COM 12008R107 46,125 4,007,377 SH   SOLE   4,007,377 0 0
Cabelas Inc. Cl A COM 126804301 2,845 51,792 SH   SOLE   51,792 0 0
Cable One Inc. COM 12685J105 1,885 3,228 SH   SOLE   3,228 0 0
Canadian Natural Resources COM 136385101 207 6,473 SH   SOLE   6,473 0 0
Carmax, Inc. COM 143130102 321,867 6,033,117 SH   SOLE   6,033,117 0 0
Caterpillar COM 149123101 721 8,119 SH   SOLE   8,119 0 0
Charter Communications Inc Del COM 16119p108 4,379 16,221 SH   SOLE   16,221 0 0
Chipotle Mexican Grill Inc COM 169656105 242,635 572,928 SH   SOLE   572,928 0 0
Coca Cola Co. COM 191216100 3,078 72,732 SH   SOLE   72,732 0 0
Comcast Corp. Cl A COM 20030n101 487 7,344 SH   SOLE   7,344 0 0
Costco Wholesale Corp COM 22160k105 77,009 504,944 SH   SOLE   504,944 0 0
Cresud SACIFYA Spon ADR Repstg COM 226406106 10,933 612,147 SH   SOLE   612,147 0 0
CVS Corp. COM 126650100 1,228 13,801 SH   SOLE   13,801 0 0
Danaher Corp. COM 235851102 142,819 1,821,908 SH   SOLE   1,821,908 0 0
Dentsply Sirona Inc. COM 24906P109 485,151 8,163,402 SH   SOLE   8,163,402 0 0
Edison International COM 281020107 3,100 42,900 SH   SOLE   42,900 0 0
Emcor Group Inc COM 29084q100 87,781 1,472,341 SH   SOLE   1,472,341 0 0
Expeditors Int'l of Wash. Inc. COM 302130109 652 12,661 SH   SOLE   12,661 0 0
Exxon Mobil Corp COM 30231g103 4,176 47,842 SH   SOLE   47,842 0 0
Fang Holdings LTD ADR COM 30711y102 4,527 1,008,260 SH   SOLE   1,008,260 0 0
Fastenal Co COM 311900104 478,592 11,455,058 SH   SOLE   11,455,058 0 0
Federal Home Loan Mortgage Cor COM 313400301 2,355 1,500,000 SH   SOLE   1,500,000 0 0
Federal National Mortgage Assn COM 313586109 2,792 1,651,820 SH   SOLE   1,651,820 0 0
Fortive Corp. COM 34959J108 38,621 758,753 SH   SOLE   758,753 0 0
Goldman Sachs Group Inc COM 38141g104 119,803 742,870 SH   SOLE   742,870 0 0
Graham Holdings Co. COM 384637104 1,554 3,228 SH   SOLE   3,228 0 0
HDFC Bank Ltd ADR Repstg 3 Shs COM 40415f101 1,121 15,592 SH   SOLE   15,592 0 0
Home Depot COM 437076102 2,638 20,500 SH   SOLE   20,500 0 0
IAC Interactivecorp COM 44919P508 75,288 1,205,190 SH   SOLE   1,205,190 0 0
IBM COM 459200101 2,286 14,394 SH   SOLE   14,394 0 0
Idexx Laboratories Corp. COM 45168D104 12,056 106,944 SH   SOLE   106,944 0 0
Ingredion Inc. COM 457187102 240 1,800 SH   SOLE   1,800 0 0
Interactive Brokers Group Inc COM 45841n107 35,338 1,001,923 SH   SOLE   1,001,923 0 0
Irsa Inversiones y Represen SA COM 450047204 4,554 239,793 SH   SOLE   239,793 0 0
Jacobs Engineering Group Inc COM 469814107 267,787 5,177,628 SH   SOLE   5,177,628 0 0
JD.com COM 47215P106 98,050 3,758,130 SH   SOLE   3,758,130 0 0
Johnson & Johnson COM 478160104 675 5,713 SH   SOLE   5,713 0 0
JP Morgan Chase & Co. COM 46625h100 67,231 1,009,625 SH   SOLE   1,009,625 0 0
Lennox International Inc. COM 526107107 1,702 10,840 SH   SOLE   10,840 0 0
Liberty Global PLC Shrs CL A COM g5480u104 8,771 256,598 SH   SOLE   256,598 0 0
LKQ Corp. COM 501889208 6,383 180,000 SH   SOLE   180,000 0 0
Lockheed Martin Corp. COM 539830109 511 2,133 SH   SOLE   2,133 0 0
Makemytrip Ltd COM v5633w109 66,406 2,813,802 SH   SOLE   2,813,802 0 0
Mastercard Inc COM 57636q104 532,613 5,233,499 SH   SOLE   5,233,499 0 0
Match Group Inc. COM 57665r106 12,471 701,000 SH   SOLE   701,000 0 0
McDonalds COM 580135101 1,602 13,885 SH   SOLE   13,885 0 0
Medtronic PLC COM G5960L103 259 3,000 SH   SOLE   3,000 0 0
Microsoft COM 594918104 955 16,576 SH   SOLE   16,576 0 0
Mohawk Industries COM 608190104 493,982 2,465,720 SH   SOLE   2,465,720 0 0
Monsanto Co COM 61166w101 507 4,957 SH   SOLE   4,957 0 0
Novo Nordisk A/S ADR COM 670100205 3,916 94,165 SH   SOLE   94,165 0 0
O Reilly Automotive Inc COM 67103h107 519,191 1,853,524 SH   SOLE   1,853,524 0 0
Och Ziff Capital Management Gr COM 67551U105 3,392 781,620 SH   SOLE   781,620 0 0
Omnicom Group COM 681919106 191,203 2,249,451 SH   SOLE   2,249,451 0 0
PepsiCo COM 713448108 4,567 41,986 SH   SOLE   41,986 0 0
Perrigo Co PLC COM G97822103 136,589 1,479,353 SH   SOLE   1,479,353 0 0
Praxair COM 74005P104 185,967 1,539,083 SH   SOLE   1,539,083 0 0
Primerica Inc COM 74164M108 213,053 4,017,602 SH   SOLE   4,017,602 0 0
Procter & Gamble COM 742718109 7,939 88,456 SH   SOLE   88,456 0 0
Progressive Corp. Ohio COM 743315103 845 26,819 SH   SOLE   26,819 0 0
Ryanair Holdings PLC ADR COM 783513104 407 5,421 SH   SOLE   5,421 0 0
Schlumberger Ltd COM 806857108 2,646 33,644 SH   SOLE   33,644 0 0
Schwab Charles Corp COM 808513105 279,039 8,838,730 SH   SOLE   8,838,730 0 0
Signet Jewelers Limited COM G81276100 227 3,046 SH   SOLE   3,046 0 0
Third Point Reinsurance LTD COM g8827u100 36,350 3,029,190 SH   SOLE   3,029,190 0 0
Tiffany & Co COM 886547108 157,035 2,162,128 SH   SOLE   2,162,128 0 0
Time Warner Inc COM 887317303 10,652 133,808 SH   SOLE   133,808 0 0
TJX Cos - New COM 872540109 831,258 11,116,041 SH   SOLE   11,116,041 0 0
Trimble Navigation Ltd. COM 896239100 586 20,505 SH   SOLE   20,505 0 0
U.S. Bancorp New - Del. COM 902973304 779 18,155 SH   SOLE   18,155 0 0
Union Pacific COM 907818108 5,930 60,800 SH   SOLE   60,800 0 0
Valeant Pharmaceuticals Intern COM 91911k102 6,775 275,963 SH   SOLE   275,963 0 0
Verisk Analytics Class A COM 92345Y106 4,488 55,216 SH   SOLE   55,216 0 0
Visa Inc Class A COM 92826C839 181,037 2,189,078 SH   SOLE   2,189,078 0 0
Wal-Mart Stores COM 931142103 64,607 895,823 SH   SOLE   895,823 0 0
Waters Corp COM 941848103 281,781 1,777,909 SH   SOLE   1,777,909 0 0
Wayfair Inc Cl A COM 94419L101 10,070 255,788 SH   SOLE   255,788 0 0
Wells Fargo & Co. New COM 949746101 241,982 5,464,817 SH   SOLE   5,464,817 0 0
West Pharmaceutical Svcs Inc C COM 955306105 31,623 424,467 SH   SOLE   424,467 0 0
Woodward Inc COM 980745103 650 10,401 SH   SOLE   10,401 0 0
Yandex NV Shs COM n97284108 56,906 2,703,355 SH   SOLE   2,703,355 0 0
Fairfax India Holdings Corp Su COM 303897102 389 35,500 SH   SOLE   35,500 0 0
JP Morgan Chase & Co Exp 10/28 WAR 46634e114 34,482 1,400,000 SH   SOLE   1,400,000 0 0