DF Dent & Co 13F-HR Quarterly holdings report by institutional manager

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
Expires:	Oct 31, 2018
Estimated average burden
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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
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