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 SPON ADR REP A 31680q104 187,565 5,299,948 SH   SOLE   5,299,948 0 0
AFFILIATED MANAGERS GROUP COM 008252108 2,729 16,645 SH   SOLE   16,645 0 0
ALIBABA GROUP HLDG LTD SPONSORED ADS 01609w102 360 3,335 SH   SOLE   3,335 0 0
ALIGN TECHNOLOGY INC COM 016255101 5,459 47,593 SH   SOLE   47,593 0 0
ALPHABET INC CAP STK CL A 02079K305 319,620 376,999 SH   SOLE   376,999 0 0
ALPHABET INC CAP STK CL C 02079K107 334,461 403,179 SH   SOLE   403,179 0 0
AMAZON COM INC COM 023135106 391,067 441,116 SH   SOLE   441,116 0 0
AMERICAN ELEC PWR INC COM 025537101 966 14,390 SH   SOLE   14,390 0 0
AMERICAN EXPRESS CO COM 025816109 1,200 15,172 SH   SOLE   15,172 0 0
ARCH CAP GROUP LTD ORD g0450a105 868 9,158 SH   SOLE   9,158 0 0
ATHENAHEALTH INC COM 04685w103 34,050 302,156 SH   SOLE   302,156 0 0
BAIDU INC SPON ADR REP A 056752108 456,260 2,644,679 SH   SOLE   2,644,679 0 0
BERKSHIRE HATHAWAY INC DEL CL A 084670108 1,024,885 4,102 SH   SOLE   4,102 0 0
BERKSHIRE HATHAWAY INC DEL CL B NEW 084670702 463,000 2,777,775 SH   SOLE   2,777,775 0 0
BUILDERS FIRSTSOURCE INC COM 12008R107 80,586 5,408,465 SH   SOLE   5,408,465 0 0
CAPITAL ONE FINL CORP COM 14040H105 140,373 1,619,813 SH   SOLE   1,619,813 0 0
CARMAX INC COM 143130102 574,647 9,703,590 SH   SOLE   9,703,590 0 0
CATERPILLAR INC DEL COM 149123101 271 2,918 SH   SOLE   2,918 0 0
CENTRAL SECS CORP COM 155123102 205 8,564 SH   SOLE   8,564 0 0
CHARTER COMMUNICATIONS INC N CL A 16119p108 5,202 15,892 SH   SOLE   15,892 0 0
CHIPOTLE MEXICAN GRILL INC COM 169656105 229,848 515,909 SH   SOLE   515,909 0 0
COCA COLA CO COM 191216100 2,195 51,730 SH   SOLE   51,730 0 0
COSTCO WHSL CORP NEW COM 22160k105 4,970 29,638 SH   SOLE   29,638 0 0
CREDIT ACCEP CORP MICH COM 225310101 192,454 965,117 SH   SOLE   965,117 0 0
CRESUD S A C I F Y A SPONSORED ADR 226406106 12,381 616,883 SH   SOLE   616,883 0 0
CVS HEALTH CORP COM 126650100 997 12,701 SH   SOLE   12,701 0 0
D R HORTON INC COM 23331a109 15,156 455,000 SH   SOLE   455,000 0 0
DANAHER CORP DEL COM 235851102 142,375 1,664,622 SH   SOLE   1,664,622 0 0
DENTSPLY SIRONA INC COM 24906P109 544,554 8,721,237 SH   SOLE   8,721,237 0 0
DISNEY WALT CO COM DISNEY 254687106 213 1,882 SH   SOLE   1,882 0 0
EDISON INTL COM 281020107 3,415 42,900 SH   SOLE   42,900 0 0
EMCOR GROUP INC COM 29084q100 88,452 1,405,115 SH   SOLE   1,405,115 0 0
ETSY INC COM 29786a106 10,471 985,000 SH   SOLE   985,000 0 0
EXPEDITORS INTL WASH INC COM 302130109 422 7,464 SH   SOLE   7,464 0 0
EXXON MOBIL CORP COM 30231g102 3,222 39,293 SH   SOLE   39,293 0 0
FACEBOOK INC CL A 30303m102 43,272 304,624 SH   SOLE   304,624 0 0
FASTENAL CO COM 311900104 229,562 4,457,511 SH   SOLE   4,457,511 0 0
FIAT CHRYSLER AUTOMOBILES N SHS n31738102 109,386 10,007,912 SH   SOLE   10,007,912 0 0
GOLDMAN SACHS GROUP INC COM 38141g104 142,570 620,624 SH   SOLE   620,624 0 0
GRAHAM HLDGS CO COM 384637104 1,199 2,000 SH   SOLE   2,000 0 0
HDFC BANK LTD ADR REPS 3 SHS 40415f101 998 13,271 SH   SOLE   13,271 0 0
IAC INTERACTIVECORP COM 44919P508 88,853 1,205,275 SH   SOLE   1,205,275 0 0
IDEXX LABS INC COM 45168D104 3,806 24,618 SH   SOLE   24,618 0 0
INTERACTIVE BROKERS GROUP IN COM 45841n107 34,787 1,001,923 SH   SOLE   1,001,923 0 0
INTERNATIONAL BUSINESS MACHS COM 459200101 475 2,730 SH   SOLE   2,730 0 0
IRSA INVERSIONES Y REP S A GLOBL DEP RCPT 450047204 11,397 465,000 SH   SOLE   465,000 0 0
JACOBS ENGR GROUP INC DEL COM 469814107 267,464 4,838,346 SH   SOLE   4,838,346 0 0
JD COM INC SPON ADR CL A 47215P106 93,330 3,000,000 SH   SOLE   3,000,000 0 0
JOHNSON & JOHNSON COM 478160104 528 4,240 SH   SOLE   4,240 0 0
JPMORGAN CHASE & CO COM 46625h100 764 8,694 SH   SOLE   8,694 0 0
JPMORGAN CHASE & CO *W EXP 10/28/201 46634e114 27,786 600,000 SH   SOLE   600,000 0 0
LENNOX INTL INC COM 526107107 1,772 10,593 SH   SOLE   10,593 0 0
LIBERTY GLOBAL PLC SHS CL A g5480u104 7,968 222,140 SH   SOLE   222,140 0 0
LIBERTY MEDIA CORP DELAWARE COM SER A FRMLA 531229870 4,157 127,121 SH   SOLE   127,121 0 0
LIBERTY MEDIA CORP DELAWARE COM SER C FRMLA 531229854 388,606 11,952,990 SH   SOLE   11,952,990 0 0
M & T BK CORP COM 55261f104 309 2,000 SH   SOLE   2,000 0 0
MASTERCARD INCORPORATED CL A 57636q104 543,857 4,835,576 SH   SOLE   4,835,576 0 0
MCDONALDS CORP COM 580135101 1,665 12,845 SH   SOLE   12,845 0 0
MEDTRONIC PLC SHS G5960L103 242 3,000 SH   SOLE   3,000 0 0
MERITAGE HOMES CORP COM 59001a102 11,592 315,000 SH   SOLE   315,000 0 0
MICROSOFT CORP COM 594918104 994 15,100 SH   SOLE   15,100 0 0
MOHAWK INDS INC COM 608190104 302,752 1,319,239 SH   SOLE   1,319,239 0 0
NOVO-NORDISK A S ADR 670100205 1,329 38,770 SH   SOLE   38,770 0 0
O REILLY AUTOMOTIVE INC NEW COM 67103h107 474,288 1,757,662 SH   SOLE   1,757,662 0 0
OMNICOM GROUP INC COM 681919106 184,760 2,143,140 SH   SOLE   2,143,140 0 0
PEPSICO INC COM 713448108 452 4,041 SH   SOLE   4,041 0 0
PERRIGO CO PLC SHS G97822103 40,994 617,478 SH   SOLE   617,478 0 0
PHILIP MORRIS INTL INC COM 718172109 226 2,000 SH   SOLE   2,000 0 0
PRICELINE GRP INC COM NEW 741503403 222,530 125,019 SH   SOLE   125,019 0 0
PRIMERICA INC COM 74164M108 206,219 2,508,752 SH   SOLE   2,508,752 0 0
PROCTER AND GAMBLE CO COM 742718109 4,508 50,175 SH   SOLE   50,175 0 0
PROGRESSIVE CORP OHIO COM 743315103 737 18,807 SH   SOLE   18,807 0 0
RYANAIR HLDGS PLC SPONSORED ADR NE 783513203 434 5,225 SH   SOLE   5,225 0 0
SCHWAB CHARLES CORP NEW COM 808513105 331,489 8,122,740 SH   SOLE   8,122,740 0 0
SIGNET JEWELERS LIMITED SHS G81276100 4,692 67,736 SH   SOLE   67,736 0 0
THIRD PT REINS LTD COM g8827u100 36,653 3,029,190 SH   SOLE   3,029,190 0 0
TIFFANY & CO NEW COM 886547108 348 3,648 SH   SOLE   3,648 0 0
TIME WARNER INC COM NEW 887317303 4,551 46,578 SH   SOLE   46,578 0 0
TJX COS INC NEW COM 872540109 741,988 9,382,756 SH   SOLE   9,382,756 0 0
TOLL BROTHERS INC COM 889478103 9,750 270,000 SH   SOLE   270,000 0 0
TRIMBLE INC COM 896239100 419 13,093 SH   SOLE   13,093 0 0
TRUPANION INC COM 898202106 25,529 1,795,300 SH   SOLE   1,795,300 0 0
UNION PAC CORP COM 907818108 4,897 46,235 SH   SOLE   46,235 0 0
VISA INC COM CL A 92826C839 149,000 1,676,605 SH   SOLE   1,676,605 0 0
WATERS CORP COM 941848103 260,912 1,669,196 SH   SOLE   1,669,196 0 0
WAYFAIR INC CL A 94419L101 20,874 515,525 SH   SOLE   515,525 0 0
WELLS FARGO & CO NEW COM 949746101 274,309 4,928,290 SH   SOLE   4,928,290 0 0
WEST PHARMACEUTICAL SVSC INC COM 955306105 4,876 59,742 SH   SOLE   59,742 0 0