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 467 60,625 SH   SOLE   60,625 0 0
3M COMPANY COM 88579y101 912 6,680 SH   SOLE   6,680 0 0
AAC HOLDINGS INC COM 000307108 42 182,000 SH   SOLE   182,000 0 0
ABBOTT LABORATORIES COM 002824100 1,141 14,459 SH   SOLE   14,459 0 0
ABBVIE INC SHS COM 00287y109 767 10,063 SH   SOLE   10,063 0 0
ACCENTURE PLC F CLASS A COM g1151c101 307 1,880 SH   SOLE   1,880 0 0
AIR PROD & CHEMICALS COM 009158106 440 2,203 SH   SOLE   2,203 0 0
ALPHABET INC CLASS C COM 02079K107 119,748 102,982 SH   SOLE   102,982 0 0
ALPHABET INC. CLASS A COM 02079k305 1,538 1,324 SH   SOLE   1,324 0 0
AMAZON.COM INC COM 023135106 127,734 65,514 SH   SOLE   65,514 0 0
AMERICAN TOWER CORP COM 03027X100 118,443 543,940 SH   SOLE   543,940 0 0
AMGEN INC. COM 031162100 980 4,836 SH   SOLE   4,836 0 0
ANSYS INC COM 03662Q105 218,006 937,783 SH   SOLE   937,783 0 0
APPLE INC COM 037833100 7,561 29,732 SH   SOLE   29,732 0 0
ATLASSIAN CORPORATION PLC COM G06242104 31,639 230,501 SH   SOLE   230,501 0 0
ATRION CORPORATION COM 049904105 4,280 6,584 SH   SOLE   6,584 0 0
AUTO DATA PROCESSING COM 053015103 1,897 13,880 SH   SOLE   13,880 0 0
BANK AMER CORP COM COM 060505104 260 12,259 SH   SOLE   12,259 0 0
BECTON DICKINSON&CO COM 075887109 443 1,928 SH   SOLE   1,928 0 0
BERKLEY W R CORP COM 084423102 1,076 20,626 SH   SOLE   20,626 0 0
BERKSHIRE HATHAWAY INC DELAWA COM 084670108 1,904 7 SH   SOLE   7 0 0
BERKSHIRE HATHAWAY INC CL B COM 084670702 6,899 37,735 SH   SOLE   37,735 0 0
BIO-TECHNE CORP COM 09073M104 150,295 792,611 SH   SOLE   792,611 0 0
BLACK KNIGHT INC COM 09215C105 92,574 1,594,460 SH   SOLE   1,594,460 0 0
BLACKLINE INC COM 09239B109 159,313 3,028,196 SH   SOLE   3,028,196 0 0
BRIGHT HORIZONS FAM SOL IN DEL COM 109194100 5,804 56,905 SH   SOLE   56,905 0 0
BROOKS AUTOMATION INC COM 114340102 59,257 1,942,841 SH   SOLE   1,942,841 0 0
CABLE ONE INC COM COM 12685J105 93,376 56,798 SH   SOLE   56,798 0 0
CALAVO GROWERS INC COM 128246105 3,770 65,355 SH   SOLE   65,355 0 0
CANADIAN NATL RAILWY F COM 136375102 1,553 20,000 SH   SOLE   20,000 0 0
CANTEL MEDICAL CORP COM 138098108 2,476 68,980 SH   SOLE   68,980 0 0
CAPITAL ONE FINL CORP COM COM 14040H105 1,305 25,891 SH   SOLE   25,891 0 0
CARMAX INC COM 143130102 80,722 1,499,570 SH   SOLE   1,499,570 0 0
CBRE GROUP INC COM 12504L109 91,853 2,435,770 SH   SOLE   2,435,770 0 0
CHEVRON CORP COM 166764100 344 4,747 SH   SOLE   4,747 0 0
CHUBB LTD COM h1467j104 453 4,056 SH   SOLE   4,056 0 0
CIGNA CORP COM 125523100 386 2,179 SH   SOLE   2,179 0 0
CISCO SYSTEMS INC COM 17275r102 2,437 61,992 SH   SOLE   61,992 0 0
COCA COLA COM COM 191216100 1,721 38,884 SH   SOLE   38,884 0 0
COGENT COMMUNICATIONS COM 19239V302 8,861 108,103 SH   SOLE   108,103 0 0
COLGATE-PALMOLIVE CO COM 194162103 783 11,800 SH   SOLE   11,800 0 0
COMCAST CORP NEW CL A COM 20030n101 2,414 70,201 SH   SOLE   70,201 0 0
CONSOLIDATED EDISON INC COM COM 209115104 316 4,053 SH   SOLE   4,053 0 0
CONSTELLATION SOFTWR F COM 21037x100 7,399 8,145 SH   SOLE   8,145 0 0
COSTAR GROUP INC COM 22160N109 124,689 212,342 SH   SOLE   212,342 0 0
COSTCO WHOLESALE CO COM 22160k105 207 727 SH   SOLE   727 0 0
COUPA SOFTWARE COM 22266l106 14,052 100,566 SH   SOLE   100,566 0 0
CROWN CASTLE REIT INC COM 22822v101 8,173 56,602 SH   SOLE   56,602 0 0
CVS HEALTH CORP COM 126650100 242 4,073 SH   SOLE   4,073 0 0
DANAHER CORP COM 235851102 101,972 736,740 SH   SOLE   736,740 0 0
DEXCOM INC COM 252131107 272 1,009 SH   SOLE   1,009 0 0
DISCOVER FINANCIAL SERVICES COM 254709108 1,823 51,098 SH   SOLE   51,098 0 0
DOLLAR GENERAL CORP COM 256677105 27,417 181,558 SH   SOLE   181,558 0 0
DOUGLAS DYNAMICS INC COM 25960R105 10,281 289,529 SH   SOLE   289,529 0 0
DUKE REALTY CORP REIT COM 264411505 355 10,950 SH   SOLE   10,950 0 0
ECOLAB INC COM 278865100 175,710 1,127,572 SH   SOLE   1,127,572 0 0
EDWARDS LIFESCIENCES COM 28176e108 2,144 11,366 SH   SOLE   11,366 0 0
EMERSON ELECTRIC CO COM 291011104 346 7,271 SH   SOLE   7,271 0 0
ENTERPRISE PRODS PART LP COM 293792107 603 42,187 SH   SOLE   42,187 0 0
ENVESTNET INC COM 29404K106 69,273 1,288,081 SH   SOLE   1,288,081 0 0
EQUITY RESIDENTIAL REIT COM 29476l107 226 3,662 SH   SOLE   3,662 0 0
EVERTEC INC COM 30040P103 3,878 170,625 SH   SOLE   170,625 0 0
EVO PAYMENTS INC COM 26927e104 6,017 393,289 SH   SOLE   393,289 0 0
EXPONENT INC COM 30214U102 4,943 68,732 SH   SOLE   68,732 0 0
EXXON MOBIL CORP COM 30231g102 858 22,605 SH   SOLE   22,605 0 0
FACEBOOK INC CLASS COM 30303m102 324 1,942 SH   SOLE   1,942 0 0
FASTENAL CO COM 311900104 130,691 4,182,102 SH   SOLE   4,182,102 0 0
FISERV INC COM 337738108 5,544 58,360 SH   SOLE   58,360 0 0
FLOOR & DECOR HOLDINGS, INC. COM 339750101 5,245 163,462 SH   SOLE   163,462 0 0
FORTINET INC COM COM 34959E109 1,038 10,263 SH   SOLE   10,263 0 0
GENERAL ELECTRIC CO COM 369604103 276 34,737 SH   SOLE   34,737 0 0
GENUINE PARTS CO COM 372460105 214 3,179 SH   SOLE   3,179 0 0
GLU MOBILE INC COM 379890106 79 12,500 SH   SOLE   12,500 0 0
GUIDEWIRE SOFTWARE INC COM 40171V100 8,882 111,992 SH   SOLE   111,992 0 0
HAMILTON LANE INC COM 407497106 9,243 167,114 SH   SOLE   167,114 0 0
HEALTHPEAK PPTYS INC COM 42250p103 1,127 47,254 SH   SOLE   47,254 0 0
HEICO CORP CL A COM 422806208 50,494 790,198 SH   SOLE   790,198 0 0
HELIOS TECHNOLOGIES ORD SHS COM 42328h109 3,765 99,281 SH   SOLE   99,281 0 0
HOME DEPOT INC COM 437076102 681 3,648 SH   SOLE   3,648 0 0
HONEYWELL INTL INC COM 438516106 355 2,655 SH   SOLE   2,655 0 0
IAA INC. COM 449253103 6,005 200,437 SH   SOLE   200,437 0 0
IBM CORP COM 459200101 527 4,753 SH   SOLE   4,753 0 0
IDEX CORP COM 45167R104 2,982 21,595 SH   SOLE   21,595 0 0
IDEXX LABS INC COM 45168d104 37,487 154,751 SH   SOLE   154,751 0 0
ILLINOIS TOOL WORKS COM 452308109 311 2,187 SH   SOLE   2,187 0 0
ILLUMINA INC COM 452327109 176,063 644,637 SH   SOLE   644,637 0 0
INTEL CORP COM 458140100 14,378 265,667 SH   SOLE   265,667 0 0
INTUITIVE SURGICAL INC COM 46120E602 150,600 304,114 SH   SOLE   304,114 0 0
J P MORGAN CHASE & CO COM 46625h100 3,913 43,466 SH   SOLE   43,466 0 0
JOHN BEAN TECHNOLOGIES COM 477839104 5,202 70,036 SH   SOLE   70,036 0 0
JOHNSON AND JOHNSON COM COM 478160104 11,319 86,319 SH   SOLE   86,319 0 0
KANSAS CITY SOUTHERN COM NEW COM 485170302 1,931 15,185 SH   SOLE   15,185 0 0
KEYON COMMUNI HOLD INC COM 493312201 0 16,667 SH   SOLE   16,667 0 0
KEYSIGHT TECHNOLOGIES INC COM 49338l103 1,824 21,803 SH   SOLE   21,803 0 0
KIMBERLY-CLARK CORP COM 494368103 347 2,713 SH   SOLE   2,713 0 0
LABORATORY CORP AMER HLDGS COM COM 50540R409 1,186 9,384 SH   SOLE   9,384 0 0
LEMAITRE VASCULAR COM 525558201 2,802 112,441 SH   SOLE   112,441 0 0
LILLY ELI & CO COM 532457108 931 6,711 SH   SOLE   6,711 0 0
LITTELFUSE INC COM 537008104 2,642 19,801 SH   SOLE   19,801 0 0
LIVE NATION COM 538034109 3,162 69,551 SH   SOLE   69,551 0 0
LOWE'S COMPANIES INC COM 548661107 2,844 33,050 SH   SOLE   33,050 0 0
M & T BANK CORP COM 55261f104 342 3,303 SH   SOLE   3,303 0 0
MAGELLAN MIDSTREAM PRTNRS LP C COM 559080106 224 6,150 SH   SOLE   6,150 0 0
MARKEL CORP HLDG CO COM 570535104 188,984 203,671 SH   SOLE   203,671 0 0
MARRIOTT INTERNATIONAL INC COM 571903202 11,673 156,030 SH   SOLE   156,030 0 0
MASTERCARD INC-CLASS A COM 57636Q104 119,792 495,910 SH   SOLE   495,910 0 0
MC DONALDS CORP COM 580135101 574 3,470 SH   SOLE   3,470 0 0
MCCORMICK & CO INC COM NON VTG COM 579780206 1,775 12,567 SH   SOLE   12,567 0 0
MERCK & CO. INC. COM 58933y105 4,193 54,502 SH   SOLE   54,502 0 0
MESA LABS INC COM 59064R109 9,494 41,992 SH   SOLE   41,992 0 0
MICROSOFT CORP COM 594918104 17,399 110,323 SH   SOLE   110,323 0 0
MIDDLEBY CORP COM 596278101 2,847 50,053 SH   SOLE   50,053 0 0
MOHAWK INDUSTRIES COM 608190104 1,190 15,610 SH   SOLE   15,610 0 0
MONRO INC COM 610236101 6,586 150,332 SH   SOLE   150,332 0 0
MOODYS CORP COM 615369105 165,293 781,527 SH   SOLE   781,527 0 0
NEOGEN CORP COM COM 640491106 831 12,400 SH   SOLE   12,400 0 0
NESTLE S A F SPONSORED ADR 1 A COM 641069406 633 6,142 SH   SOLE   6,142 0 0
NEXTERA ENERGY INC SHS COM 65339f101 201 834 SH   SOLE   834 0 0
NORFOLK SOUTHERN CO COM 655844108 2,315 15,853 SH   SOLE   15,853 0 0
NOVANTA INC COM NPV COM 67000b104 8,852 110,813 SH   SOLE   110,813 0 0
NOVARTIS AG F SPONSORED ADR 1 COM 66987v109 425 5,150 SH   SOLE   5,150 0 0
NUTRIEN LTD COM 67077m108 945 27,855 SH   SOLE   27,855 0 0
O REILLY AUTOMOTIVE COM 67103h107 13,473 44,752 SH   SOLE   44,752 0 0
OKTA, INC COM 679295105 72,131 589,982 SH   SOLE   589,982 0 0
OLD DOMINION FGHT LINES INC CO COM 679580100 18,354 139,831 SH   SOLE   139,831 0 0
ONESPAWORLD HOLDINGS LTD COM P73684113 2,310 568,924 SH   SOLE   568,924 0 0
ORTHOPEDIATRICS CORP COM 68752L100 12,158 306,715 SH   SOLE   306,715 0 0
PAYCHEX INC COM 704326107 3,025 48,080 SH   SOLE   48,080 0 0
PEPSICO INC COM 713448108 1,477 12,298 SH   SOLE   12,298 0 0
PFIZER INC COM 717081103 1,883 57,679 SH   SOLE   57,679 0 0
PINNACLE WEST CAP CORP COM 723484101 228 3,008 SH   SOLE   3,008 0 0
PNC FINL SERVICES COM 693475105 628 6,563 SH   SOLE   6,563 0 0
POOL CORPORATION COM 73278l105 521 2,648 SH   SOLE   2,648 0 0
PRICE T ROWE GROUP INC COM 74144T108 8,949 91,643 SH   SOLE   91,643 0 0
PROCTER & GAMBLE CO COM 742718109 15,949 144,989 SH   SOLE   144,989 0 0
PROS HOLDINGS INC COM 74346Y103 99,735 3,214,146 SH   SOLE   3,214,146 0 0
QUALCOMM INC COM 747525103 21,168 312,905 SH   SOLE   312,905 0 0
QUALYS INC COM COM 74758t303 89,694 1,031,085 SH   SOLE   1,031,085 0 0
REPLIGEN CORPORATION COM 759916109 2,688 27,848 SH   SOLE   27,848 0 0
ROPER TECHNOLOGIES INC COM 776696106 170,178 545,776 SH   SOLE   545,776 0 0
RPM INTERNATIONAL INC COM 749685103 248 4,175 SH   SOLE   4,175 0 0
S & P GLOBAL INC COM 78409V104 123,177 502,661 SH   SOLE   502,661 0 0
SBA COMMUNICATIONS CORP CL A COM 78410G104 91,690 339,630 SH   SOLE   339,630 0 0
SEI INVESTMENTS CO COM 784117103 438 9,451 SH   SOLE   9,451 0 0
SERVICE CORP INTL COM 817565104 274 7,000 SH   SOLE   7,000 0 0
SITEONE LANDSCAPE SUPPLY, INC. COM 82982L103 9,000 122,252 SH   SOLE   122,252 0 0
SMITH A O COM 831865209 358 9,467 SH   SOLE   9,467 0 0
SOUTHERN COMPANY COM 842587107 214 3,949 SH   SOLE   3,949 0 0
STERIS PLC COM G8473t100 483 3,451 SH   SOLE   3,451 0 0
TELADOC INC COM 87918A105 10,098 65,141 SH   SOLE   65,141 0 0
TELEFLEX INC COM COM 879369106 107,091 365,673 SH   SOLE   365,673 0 0
THE DESCARTES SYSTEMS GROUP IN COM 249906108 5,315 154,545 SH   SOLE   154,545 0 0
THERMO FISHER SCIENTIFIC INC COM 883556102 92,856 327,419 SH   SOLE   327,419 0 0
TRACTOR SUPPLY COMP COM 892356106 761 9,002 SH   SOLE   9,002 0 0
TRANSDIGM GROUP INC COM 893641100 102,690 320,716 SH   SOLE   320,716 0 0
TREX COMPANY, INC. COM 89531P105 9,046 112,873 SH   SOLE   112,873 0 0
TRIMBLE INC COM 896239100 1,468 46,124 SH   SOLE   46,124 0 0
TRUIST FINANCIAL ORD SHS COM 89832Q109 395 12,818 SH   SOLE   12,818 0 0
TRUPANION, INC. COM 898202106 5,547 213,104 SH   SOLE   213,104 0 0
TWILIO INC. COM 90138F102 24,637 275,310 SH   SOLE   275,310 0 0
TYLER TECHNOLOGIES INC COM 902252105 126,437 426,347 SH   SOLE   426,347 0 0
U S BANCORP COM 902973304 856 24,849 SH   SOLE   24,849 0 0
UNION PACIFIC CORP COM 907818108 238 1,691 SH   SOLE   1,691 0 0
UNITED PARCEL SRVC CLASS B COM 911312106 223 2,391 SH   SOLE   2,391 0 0
UNITED TECHNOLOGIES CORP. COM 913017109 536 5,680 SH   SOLE   5,680 0 0
UNITEDHEALTH GRP INC COM 91324p102 2,017 8,089 SH   SOLE   8,089 0 0
VEEVA SYSTEMS, INC. COM 922475108 54,421 348,027 SH   SOLE   348,027 0 0
VENTAS INC REIT COM 92276f100 545 20,339 SH   SOLE   20,339 0 0
VERISK ANALYTICS INC COM 92345Y106 171,027 1,227,058 SH   SOLE   1,227,058 0 0
VERIZON COMMUNICATN COM 92343v104 830 15,456 SH   SOLE   15,456 0 0
VISA INC CL A COM 92826C839 187,539 1,163,971 SH   SOLE   1,163,971 0 0
VULCAN MATERIALS CO COM 929160109 158,070 1,462,659 SH   SOLE   1,462,659 0 0
W.P. CAREY INC. REIT COM 92936u109 296 5,095 SH   SOLE   5,095 0 0
WABTEC COM 929740108 1,560 32,410 SH   SOLE   32,410 0 0
WALMART INC COM 931142103 505 4,444 SH   SOLE   4,444 0 0
WALT DISNEY CO COM 254687106 562 5,816 SH   SOLE   5,816 0 0
WASTE CONNECTIONS INC COM 94106B101 177,544 2,290,893 SH   SOLE   2,290,893 0 0
WATSCO INC COM 942622200 3,623 22,929 SH   SOLE   22,929 0 0
WAYFAIR COM 94419L101 3,516 65,792 SH   SOLE   65,792 0 0
WD-40 COMPANY COM 929236107 3,536 17,605 SH   SOLE   17,605 0 0
WELLS FARGO BK N A COM 949746101 1,552 54,082 SH   SOLE   54,082 0 0
ISHARES CORE S&P MID CAP ETF ETFS 464287507 911 6,334 SH   SOLE   6,334 0 0
ISHARES CORE S&P SMALL CAP ETF ETFS 464287804 348 6,199 SH   SOLE   6,199 0 0
ISHARES MSCI EAFE ETF ETFS 464287465 543 10,157 SH   SOLE   10,157 0 0
SPDR GOLD TRUST ETFS 78463v107 227 1,533 SH   SOLE   1,533 0 0
VANGUARD DIVIDEND APPREC ETFS 921908844 1,123 10,858 SH   SOLE   10,858 0 0
VANGUARD FTSE ALL WORLD EX US ETFS 922042775 2,665 64,974 SH   SOLE   64,974 0 0
VANGUARD FTSE EMERGING MARKETS ETFS 922042858 598 17,836 SH   SOLE   17,836 0 0
VANGUARD HIGH DIVIDEND YIELD E ETFS 921946406 673 9,517 SH   SOLE   9,517 0 0
VANGUARD MID CAP ETF ETFS 922908629 333 2,533 SH   SOLE   2,533 0 0
VANGUARD REIT ETF ETFS 922908553 1,059 15,160 SH   SOLE   15,160 0 0
VANGUARD S&P 500 ETF ETFS 922908363 4,605 19,447 SH   SOLE   19,447 0 0
VANGUARD TOTAL STK MKT ETF ETFS 922908769 337 2,615 SH   SOLE   2,615 0 0