Since 2001, the Texas Rangers and the Florida Marlins are tied for the most runs in a loss, with 17 runs.

Interpreted as:

MLB most runs in a regular-season loss after 2000

	TEAM	R	L	DATE	TM		OPP	RESULT	W	L%	AB	H	2B	3B	HR	RBI	BB	HBP	SO	SB	CS	PA	TB	XBH	SH	SF	IBB	GIDP	AVG	OBP	SLG	OPS
1	Rangers	17	1	8/12/2008	TEX	@	BOS	L 17-19	0	1.000	47	20	7	0	1	17	3	1	6	0	0	53	30	8	0	2	0	0	.426	.453	.638	1.091
2	Marlins	17	1	7/4/2008	FLA	@	COL	L 17-18	0	1.000	47	22	7	0	2	17	6	2	4	0	0	56	35	9	1	0	1	1	.468	.545	.745	1.290
3	Tigers	15	1	5/8/2004	DET	@	TEX	L 15-16	0	1.000	45	16	3	0	1	15	6	1	7	1	0	53	22	4	1	0	0	0	.356	.442	.489	.931
4	Twins	14	1	7/28/2021	MIN	vs	DET	L 14-17	0	1.000	43	16	1	0	7	14	7	1	8	0	0	51	38	8	0	0	0	0	.372	.471	.884	1.354
5	Nationals	14	1	8/17/2019	WSH	vs	MIL	L 14-15	0	1.000	58	18	6	0	4	13	10	0	13	1	0	69	36	10	0	1	2	2	.310	.406	.621	1.026
6	Marlins	14	1	9/2/2008	FLA	vs	ATL	L 14-16	0	1.000	43	15	4	1	2	13	7	0	10	2	0	51	27	7	0	1	1	0	.349	.431	.628	1.059
7	White Sox	14	1	7/6/2007	CWS	vs	MIN	L 14-20	0	1.000	44	18	5	1	3	14	4	1	7	0	0	49	34	9	0	0	0	0	.409	.469	.773	1.242
8	White Sox	14	1	6/19/2004	CWS	@	MON	L 14-17	0	1.000	41	15	4	0	2	14	7	2	5	0	1	50	25	6	0	0	1	1	.366	.480	.610	1.090
9	Padres	14	1	8/29/2001	SDP	@	STL	L 14-16	0	1.000	43	15	4	0	4	14	6	0	11	1	0	49	31	8	0	0	1	1	.349	.429	.721	1.150
10	Mariners	14	1	8/5/2001	SEA	@	CLE	L 14-15	0	1.000	50	17	4	0	0	13	2	1	7	0	0	54	21	4	0	1	0	0	.340	.370	.420	.790
11	Braves	13	1	7/18/2023	ATL	vs	ARI	L 13-16	0	1.000	37	11	4	0	3	13	4	0	5	1	0	41	24	7	0	0	0	0	.297	.366	.649	1.015
12	Cubs	13	1	8/27/2021	CHC	@	CWS	L 13-17	0	1.000	39	13	3	0	4	12	3	0	12	0	2	42	28	7	0	0	0	0	.333	.381	.718	1.099
13	Pirates	13	1	8/7/2020	PIT	vs	DET	L 13-17	0	1.000	47	16	2	0	3	13	4	0	8	0	0	52	27	5	0	1	0	1	.340	.385	.574	.959
14	Red Sox	13	1	6/29/2019	BOS	vs	NYY	L 13-17	0	1.000	43	18	3	0	3	12	6	0	5	0	0	50	30	6	0	1	0	1	.419	.480	.698	1.178
15	Rockies	13	1	6/16/2019	COL	vs	SDP	L 13-14	0	1.000	46	19	5	0	2	13	2	0	14	0	0	48	30	7	0	0	1	0	.413	.438	.652	1.090
16	Padres	13	1	6/2/2016	SDP	vs	SEA	L 13-16	0	1.000	47	20	2	1	0	11	3	1	10	0	0	51	24	3	0	0	0	1	.426	.471	.511	.981
17	Red Sox	13	1	8/23/2012	BOS	vs	LAA	L 13-14	0	1.000	48	18	4	0	3	13	1	0	12	1	1	49	31	7	0	0	0	0	.375	.388	.646	1.034
18	Phillies	13	1	5/2/2012	PHI	@	ATL	L 13-15	0	1.000	49	17	4	0	1	13	5	1	9	2	0	55	24	5	0	0	0	1	.347	.418	.490	.908
19	Twins	13	1	7/20/2009	MIN	@	OAK	L 13-14	0	1.000	41	17	3	0	4	13	8	0	7	0	0	50	32	7	0	1	1	1	.415	.500	.780	1.280
20	Rangers	13	1	9/19/2008	TEX	vs	LAA	L 13-15	0	1.000	46	19	2	2	2	11	1	0	12	0	0	47	31	6	0	0	0	1	.413	.426	.674	1.099
21	Royals	13	1	8/23/2006	KCR	vs	CLE	L 13-15	0	1.000	50	19	3	1	2	13	4	0	12	1	0	54	30	6	0	0	0	0	.380	.426	.600	1.026
22	Rangers	13	1	5/16/2006	TEX	@	NYY	L 13-14	0	1.000	40	17	5	0	2	12	5	1	5	0	0	47	28	7	1	0	0	1	.425	.500	.700	1.200
23	Blue Jays	13	1	6/24/2004	TOR	vs	TBD	L 13-19	0	1.000	42	15	4	0	4	13	5	2	2	0	0	49	31	8	0	0	0	2	.357	.449	.738	1.187
24	Diamondbacks	12	1	5/17/2025	AZ	vs	COL	L 12-14	0	1.000	43	15	5	1	2	10	4	1	7	2	0	49	28	8	0	1	0	0	.349	.408	.651	1.059
25	Twins	12	1	7/5/2024	MIN	vs	HOU	L 12-13	0	1.000	42	17	5	0	2	12	4	1	9	0	0	48	28	7	1	0	0	1	.405	.468	.667	1.135