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
3-D SYS CORP DEL COM NEW COM 88554D205 424 60,625 SH   SOLE   60,625 0 0
3M COMPANY COM 88579y101 1,042 6,680 SH   SOLE   6,680 0 0
AAC HOLDINGS INC COM 000307108 7 182,000 SH   SOLE   182,000 0 0
ABBOTT LABORATORIES COM 002824100 1,322 14,459 SH   SOLE   14,459 0 0
ABBVIE INC SHS COM 00287y109 1,013 10,313 SH   SOLE   10,313 0 0
ACCENTURE PLC F CLASS A COM g1151c101 404 1,883 SH   SOLE   1,883 0 0
ADOBE SYSTEMS INC COM 00724F101 217 498 SH   SOLE   498 0 0
AIR PROD & CHEMICALS COM 009158106 532 2,203 SH   SOLE   2,203 0 0
ALARM.COM COM 011642105 3,665 56,544 SH   SOLE   56,544 0 0
ALPHABET INC CLASS C COM 02079K107 133,842 94,681 SH   SOLE   94,681 0 0
ALPHABET INC. CLASS A COM 02079k305 1,880 1,326 SH   SOLE   1,326 0 0
AMAZON.COM INC COM 023135106 168,396 61,039 SH   SOLE   61,039 0 0
AMERICAN TOWER CORP COM 03027X100 159,621 617,395 SH   SOLE   617,395 0 0
AMGEN INC. COM 031162100 916 3,884 SH   SOLE   3,884 0 0
ANSYS INC COM 03662Q105 258,766 887,005 SH   SOLE   887,005 0 0
APPLE INC COM 037833100 10,782 29,555 SH   SOLE   29,555 0 0
AT&T INC COM 00206r102 243 8,028 SH   SOLE   8,028 0 0
ATLASSIAN CORPORATION PLC COM G06242104 43,489 241,245 SH   SOLE   241,245 0 0
ATRION CORPORATION COM 049904105 6,228 9,777 SH   SOLE   9,777 0 0
AUTO DATA PROCESSING COM 053015103 2,069 13,897 SH   SOLE   13,897 0 0
BANK AMER CORP COM COM 060505104 344 14,472 SH   SOLE   14,472 0 0
BECTON DICKINSON&CO COM 075887109 461 1,928 SH   SOLE   1,928 0 0
BERKLEY W R CORP COM 084423102 1,278 22,301 SH   SOLE   22,301 0 0
BERKSHIRE HATHAWAY INC DELAWA COM 084670108 1,871 7 SH   SOLE   7 0 0
BERKSHIRE HATHAWAY INC CL B COM 084670702 6,405 35,883 SH   SOLE   35,883 0 0
BIO-TECHNE CORP COM 09073M104 224,837 851,429 SH   SOLE   851,429 0 0
BLACK KNIGHT INC COM 09215C105 121,453 1,673,833 SH   SOLE   1,673,833 0 0
BLACKLINE INC COM 09239B109 208,380 2,513,324 SH   SOLE   2,513,324 0 0
BRIGHT HORIZONS FAM SOL IN DEL COM 109194100 30,017 256,119 SH   SOLE   256,119 0 0
BRISTOL-MYERS SQUIBB COM 110122108 226 3,851 SH   SOLE   3,851 0 0
BRITISH AMER TOBACCO PLC ADR COM 110448107 210 5,402 SH   SOLE   5,402 0 0
BROOKS AUTOMATION INC COM 114340102 54,452 1,230,827 SH   SOLE   1,230,827 0 0
CABLE ONE INC COM COM 12685J105 140,275 79,035 SH   SOLE   79,035 0 0
CALAVO GROWERS INC COM 128246105 4,348 69,112 SH   SOLE   69,112 0 0
CANADIAN NATL RAILWY F COM 136375102 1,284 14,500 SH   SOLE   14,500 0 0
CANTEL MEDICAL CORP COM 138098108 3,299 74,595 SH   SOLE   74,595 0 0
CAPITAL ONE FINL CORP COM COM 14040H105 1,613 25,766 SH   SOLE   25,766 0 0
CARMAX INC COM 143130102 137,382 1,534,143 SH   SOLE   1,534,143 0 0
CBRE GROUP INC COM 12504L109 126,516 2,797,781 SH   SOLE   2,797,781 0 0
CHEVRON CORP COM 166764100 345 3,871 SH   SOLE   3,871 0 0
CHUBB LTD COM h1467j104 513 4,050 SH   SOLE   4,050 0 0
CIGNA CORP COM 125523100 397 2,114 SH   SOLE   2,114 0 0
CISCO SYSTEMS INC COM 17275r102 3,002 64,375 SH   SOLE   64,375 0 0
COCA COLA COM COM 191216100 1,730 38,713 SH   SOLE   38,713 0 0
COGENT COMMUNICATIONS COM 19239V302 8,752 113,138 SH   SOLE   113,138 0 0
COLGATE-PALMOLIVE CO COM 194162103 864 11,800 SH   SOLE   11,800 0 0
COMCAST CORP NEW CL A COM 20030n101 2,584 66,301 SH   SOLE   66,301 0 0
CONSTELLATION SOFTWR F COM 21037x100 8,694 7,684 SH   SOLE   7,684 0 0
COSTAR GROUP INC COM 22160N109 152,058 213,964 SH   SOLE   213,964 0 0
COSTCO WHOLESALE CO COM 22160k105 220 727 SH   SOLE   727 0 0
COUPA SOFTWARE COM 22266l106 22,940 82,803 SH   SOLE   82,803 0 0
CROWN CASTLE REIT INC COM 22822v101 9,113 54,454 SH   SOLE   54,454 0 0
CVS HEALTH CORP COM 126650100 292 4,499 SH   SOLE   4,499 0 0
DANAHER CORP COM 235851102 132,236 747,813 SH   SOLE   747,813 0 0
DISCOVER FINANCIAL SERVICES COM 254709108 1,718 34,308 SH   SOLE   34,308 0 0
DOLLAR GENERAL CORP COM 256677105 34,734 182,323 SH   SOLE   182,323 0 0
DOUGLAS DYNAMICS INC COM 25960R105 11,119 316,586 SH   SOLE   316,586 0 0
DUKE REALTY CORP REIT COM 264411505 372 10,500 SH   SOLE   10,500 0 0
EAST WEST BANCORP INC COM 27579r104 272 7,500 SH   SOLE   7,500 0 0
ECOLAB INC COM 278865100 226,466 1,138,308 SH   SOLE   1,138,308 0 0
EDWARDS LIFESCIENCES COM 28176e108 2,357 34,098 SH   SOLE   34,098 0 0
EMERSON ELECTRIC CO COM 291011104 462 7,443 SH   SOLE   7,443 0 0
ENERGY TRANSFER LP COM 29273v100 93 13,033 SH   SOLE   13,033 0 0
ENTERPRISE PRODS PART LP COM 293792107 731 40,212 SH   SOLE   40,212 0 0
ENVESTNET INC COM 29404K106 99,668 1,355,284 SH   SOLE   1,355,284 0 0
EQUITY RESIDENTIAL REIT COM 29476l107 202 3,426 SH   SOLE   3,426 0 0
EVERTEC INC COM 30040P103 5,085 180,962 SH   SOLE   180,962 0 0
EVO PAYMENTS INC COM 26927e104 9,810 429,684 SH   SOLE   429,684 0 0
EXACT SCIENCES CORP COM COM 30063p105 235 2,700 SH   SOLE   2,700 0 0
EXPONENT INC COM 30214U102 8,237 101,775 SH   SOLE   101,775 0 0
EXXON MOBIL CORP COM 30231g102 870 19,457 SH   SOLE   19,457 0 0
FACEBOOK INC CLASS COM 30303m102 424 1,867 SH   SOLE   1,867 0 0
FASTENAL CO COM 311900104 170,156 3,971,902 SH   SOLE   3,971,902 0 0
FISERV INC COM 337738108 5,116 52,406 SH   SOLE   52,406 0 0
FLOOR & DECOR HOLDINGS, INC. COM 339750101 9,992 173,316 SH   SOLE   173,316 0 0
FORTINET INC COM COM 34959E109 1,409 10,263 SH   SOLE   10,263 0 0
GENERAL ELECTRIC CO COM 369604103 246 35,994 SH   SOLE   35,994 0 0
GENUINE PARTS CO COM 372460105 268 3,079 SH   SOLE   3,079 0 0
GLU MOBILE INC COM 379890106 116 12,500 SH   SOLE   12,500 0 0
GUIDEWIRE SOFTWARE INC COM 40171V100 13,140 118,543 SH   SOLE   118,543 0 0
HAMILTON LANE INC COM 407497106 11,876 176,273 SH   SOLE   176,273 0 0
HEALTHEQUITY, INC. COM 42226A107 5,376 91,638 SH   SOLE   91,638 0 0
HEALTHPEAK PPTYS INC COM 42250p103 1,269 46,032 SH   SOLE   46,032 0 0
HEICO CORP CL A COM 422806208 81,093 998,188 SH   SOLE   998,188 0 0
HELIOS TECHNOLOGIES ORD SHS COM 42328h109 3,920 105,243 SH   SOLE   105,243 0 0
HOME DEPOT INC COM 437076102 838 3,344 SH   SOLE   3,344 0 0
HONEYWELL INTL INC COM 438516106 367 2,539 SH   SOLE   2,539 0 0
IAA INC. COM 449253103 10,130 262,634 SH   SOLE   262,634 0 0
IBM CORP COM 459200101 580 4,806 SH   SOLE   4,806 0 0
IDEX CORP COM 45167R104 3,357 21,244 SH   SOLE   21,244 0 0
IDEXX LABS INC COM 45168d104 80,534 243,924 SH   SOLE   243,924 0 0
ILLINOIS TOOL WORKS COM 452308109 386 2,208 SH   SOLE   2,208 0 0
ILLUMINA INC COM 452327109 236,250 637,911 SH   SOLE   637,911 0 0
INTEL CORP COM 458140100 15,590 260,564 SH   SOLE   260,564 0 0
INTUITIVE SURGICAL INC COM 46120E602 177,451 311,411 SH   SOLE   311,411 0 0
J P MORGAN CHASE & CO COM 46625h100 4,043 42,984 SH   SOLE   42,984 0 0
JOHN BEAN TECHNOLOGIES COM 477839104 6,495 75,505 SH   SOLE   75,505 0 0
JOHNSON AND JOHNSON COM COM 478160104 11,954 85,001 SH   SOLE   85,001 0 0
KANSAS CITY SOUTHERN COM NEW COM 485170302 2,180 14,602 SH   SOLE   14,602 0 0
KEYON COMMUNI HOLD INC COM 493312201 0 16,667 SH   SOLE   16,667 0 0
KEYSIGHT TECHNOLOGIES INC COM 49338l103 2,173 21,566 SH   SOLE   21,566 0 0
KIMBERLY-CLARK CORP COM 494368103 398 2,813 SH   SOLE   2,813 0 0
LABORATORY CORP AMER HLDGS COM COM 50540R409 1,559 9,384 SH   SOLE   9,384 0 0
LEMAITRE VASCULAR COM 525558201 3,214 121,748 SH   SOLE   121,748 0 0
LILLY ELI & CO COM 532457108 1,299 7,911 SH   SOLE   7,911 0 0
LITTELFUSE INC COM 537008104 3,728 21,848 SH   SOLE   21,848 0 0
LOWE'S COMPANIES INC COM 548661107 3,570 26,419 SH   SOLE   26,419 0 0
M & T BANK CORP COM 55261f104 343 3,302 SH   SOLE   3,302 0 0
MAGELLAN MIDSTREAM PRTNRS LP C COM 559080106 265 6,150 SH   SOLE   6,150 0 0
MARKEL CORP HLDG CO COM 570535104 193,589 209,700 SH   SOLE   209,700 0 0
MARTIN MARIETTA MATLS INC COM COM 573284106 893 4,322 SH   SOLE   4,322 0 0
MASTERCARD INC-CLASS A COM 57636Q104 146,914 496,834 SH   SOLE   496,834 0 0
MC DONALDS CORP COM 580135101 640 3,470 SH   SOLE   3,470 0 0
MCCORMICK & CO INC COM NON VTG COM 579780206 2,119 11,809 SH   SOLE   11,809 0 0
MERCK & CO. INC. COM 58933y105 4,369 56,503 SH   SOLE   56,503 0 0
MERGENET SOLUTIONS INC COM COM 58950m109 10 10,000 SH   SOLE   10,000 0 0
MESA LABS INC COM 59064R109 9,650 44,509 SH   SOLE   44,509 0 0
MICROSOFT CORP COM 594918104 22,957 112,806 SH   SOLE   112,806 0 0
MIDDLEBY CORP COM 596278101 2,555 32,372 SH   SOLE   32,372 0 0
MONRO INC COM 610236101 8,738 159,040 SH   SOLE   159,040 0 0
MOODYS CORP COM 615369105 193,422 704,045 SH   SOLE   704,045 0 0
NASPERS SPON ADR EACH REP 0.2 COM 631512209 247 6,750 SH   SOLE   6,750 0 0
NEOGEN CORP COM COM 640491106 962 12,400 SH   SOLE   12,400 0 0
NESTLE S A F SPONSORED ADR 1 A COM 641069406 678 6,142 SH   SOLE   6,142 0 0
NEXTERA ENERGY INC SHS COM 65339f101 202 842 SH   SOLE   842 0 0
NORFOLK SOUTHERN CO COM 655844108 2,776 15,813 SH   SOLE   15,813 0 0
NOVANTA INC COM NPV COM 67000b104 10,535 98,670 SH   SOLE   98,670 0 0
NOVARTIS AG F SPONSORED ADR 1 COM 66987v109 478 5,475 SH   SOLE   5,475 0 0
NUTRIEN LTD COM 67077m108 612 19,055 SH   SOLE   19,055 0 0
O REILLY AUTOMOTIVE COM 67103h107 18,365 43,552 SH   SOLE   43,552 0 0
OKTA, INC COM 679295105 88,578 442,380 SH   SOLE   442,380 0 0
OLD DOMINION FGHT LINES INC CO COM 679580100 25,597 150,935 SH   SOLE   150,935 0 0
ORTHOPEDIATRICS CORP COM 68752L100 13,819 315,793 SH   SOLE   315,793 0 0
PAYCHEX INC COM 704326107 3,552 46,893 SH   SOLE   46,893 0 0
PEPSICO INC COM 713448108 1,625 12,288 SH   SOLE   12,288 0 0
PFIZER INC COM 717081103 2,065 63,158 SH   SOLE   63,158 0 0
PINNACLE WEST CAP CORP COM 723484101 220 3,000 SH   SOLE   3,000 0 0
PNC FINL SERVICES COM 693475105 691 6,571 SH   SOLE   6,571 0 0
POOL CORPORATION COM 73278l105 720 2,648 SH   SOLE   2,648 0 0
PRICE T ROWE GROUP INC COM 74144T108 11,336 91,793 SH   SOLE   91,793 0 0
PROCTER & GAMBLE CO COM 742718109 16,860 141,006 SH   SOLE   141,006 0 0
PROS HOLDINGS INC COM 74346Y103 146,272 3,292,185 SH   SOLE   3,292,185 0 0
QUALCOMM INC COM 747525103 29,552 323,997 SH   SOLE   323,997 0 0
QUALYS INC COM COM 74758t303 92,156 885,946 SH   SOLE   885,946 0 0
RAYTHEON TECHNOLOGIES ORD SHS COM 75513e101 448 7,276 SH   SOLE   7,276 0 0
REALTY INCM CRP MD PV$1.REIT COM 756109104 282 4,740 SH   SOLE   4,740 0 0
REPLIGEN CORPORATION COM 759916109 5,476 44,300 SH   SOLE   44,300 0 0
ROPER TECHNOLOGIES INC COM 776696106 215,770 555,736 SH   SOLE   555,736 0 0
RPM INTERNATIONAL INC COM 749685103 313 4,175 SH   SOLE   4,175 0 0
S & P GLOBAL INC COM 78409V104 150,048 455,407 SH   SOLE   455,407 0 0
SALESFORCE.COM INC COM 79466L302 233 1,242 SH   SOLE   1,242 0 0
SBA COMMUNICATIONS CORP CL A COM 78410G104 106,866 358,706 SH   SOLE   358,706 0 0
SEI INVESTMENTS CO COM 784117103 498 9,053 SH   SOLE   9,053 0 0
SERVICE CORP INTL COM 817565104 282 7,247 SH   SOLE   7,247 0 0
SITEONE LANDSCAPE SUPPLY, INC. COM 82982L103 14,772 129,615 SH   SOLE   129,615 0 0
SMITH A O COM 831865209 433 9,192 SH   SOLE   9,192 0 0
STERIS PLC COM G8473t100 284 1,851 SH   SOLE   1,851 0 0
TELADOC INC COM 87918A105 8,987 47,091 SH   SOLE   47,091 0 0
TELEFLEX INC COM COM 879369106 143,963 395,525 SH   SOLE   395,525 0 0
THE DESCARTES SYSTEMS GROUP IN COM 249906108 8,613 162,820 SH   SOLE   162,820 0 0
THERMO FISHER SCIENTIFIC INC COM 883556102 119,645 330,201 SH   SOLE   330,201 0 0
TRANSDIGM GROUP INC COM 893641100 145,202 328,474 SH   SOLE   328,474 0 0
TREX COMPANY, INC. COM 89531P105 14,796 113,756 SH   SOLE   113,756 0 0
TRIMBLE INC COM 896239100 661 15,315 SH   SOLE   15,315 0 0
TRUIST FINANCIAL ORD SHS COM 89832Q109 465 12,394 SH   SOLE   12,394 0 0
TRUPANION, INC. COM 898202106 9,581 224,437 SH   SOLE   224,437 0 0
TWILIO INC. COM 90138F102 55,129 251,251 SH   SOLE   251,251 0 0
TYLER TECHNOLOGIES INC COM 902252105 110,087 317,362 SH   SOLE   317,362 0 0
U S BANCORP COM 902973304 902 24,500 SH   SOLE   24,500 0 0
UNION PACIFIC CORP COM 907818108 256 1,516 SH   SOLE   1,516 0 0
UNITED PARCEL SRVC CLASS B COM 911312106 266 2,391 SH   SOLE   2,391 0 0
UNITEDHEALTH GRP INC COM 91324p102 2,349 7,964 SH   SOLE   7,964 0 0
VEEVA SYSTEMS, INC. COM 922475108 85,328 363,996 SH   SOLE   363,996 0 0
VENTAS INC REIT COM 92276f100 715 19,524 SH   SOLE   19,524 0 0
VERISK ANALYTICS INC COM 92345Y106 208,194 1,223,233 SH   SOLE   1,223,233 0 0
VERIZON COMMUNICATN COM 92343v104 979 17,762 SH   SOLE   17,762 0 0
VISA INC CL A COM 92826C839 226,387 1,171,957 SH   SOLE   1,171,957 0 0
VULCAN MATERIALS CO COM 929160109 172,515 1,489,121 SH   SOLE   1,489,121 0 0
W.P. CAREY INC. REIT COM 92936u109 381 5,625 SH   SOLE   5,625 0 0
WABTEC COM 929740108 2,241 38,925 SH   SOLE   38,925 0 0
WALMART INC COM 931142103 592 4,941 SH   SOLE   4,941 0 0
WALT DISNEY CO COM 254687106 509 4,562 SH   SOLE   4,562 0 0
WASTE CONNECTIONS INC COM 94106B101 249,575 2,660,999 SH   SOLE   2,660,999 0 0
WATSCO INC COM 942622200 4,074 22,929 SH   SOLE   22,929 0 0
WAYFAIR COM 94419L101 9,068 45,889 SH   SOLE   45,889 0 0
WD-40 COMPANY COM 929236107 3,724 18,780 SH   SOLE   18,780 0 0
WELLS FARGO BK N A COM 949746101 1,985 77,538 SH   SOLE   77,538 0 0
ISHARES MSCI EAFE ETF ETFS 464287465 618 10,157 SH   SOLE   10,157 0 0
SPDR GOLD TRUST ETFS 78463v107 257 1,533 SH   SOLE   1,533 0 0
VANGUARD DIVIDEND APPREC ETFS 921908844 1,272 10,858 SH   SOLE   10,858 0 0
VANGUARD FTSE ALL WORLD EX US ETFS 922042775 3,012 63,257 SH   SOLE   63,257 0 0
VANGUARD FTSE EMERGING MARKETS ETFS 922042858 697 17,598 SH   SOLE   17,598 0 0
VANGUARD HIGH DIVIDEND YIELD E ETFS 921946406 750 9,517 SH   SOLE   9,517 0 0
VANGUARD INDEX FDS SMALL CP ET ETFS 922908751 221 1,515 SH   SOLE   1,515 0 0
VANGUARD MID CAP ETF ETFS 922908629 442 2,697 SH   SOLE   2,697 0 0
VANGUARD REIT ETF ETFS 922908553 1,165 14,836 SH   SOLE   14,836 0 0
VANGUARD S&P 500 ETF ETFS 922908363 4,495 15,861 SH   SOLE   15,861 0 0
VANGUARD TOTAL STK MKT ETF ETFS 922908769 448 2,862 SH   SOLE   2,862 0 0