What moves together, and what catches up a day later

Every week we test every pair of 6,902 US stocks and ETFs over the last 504 trading days, on the same day and one day apart. That's all 23,815,351 pairs, with no shortlist. Below are the relationships that survive multiple-testing correction and hold up on held-out recent data.

Pairs tested: 23,815,351
Significant same-day: 5,013,548
Catch-up followers: 5 282 pairs
Duplicate funds: 685 in 155 groups

Next-day catch-up

The follower tends to repeat the leader's move one trading day later. One row per follower, showing its strongest leader. This mostly happens in thinly traded names, whose last trade often comes before the rest of the market has finished moving. Check the follower's daily dollar volume: on a few hundred thousand dollars a day, the bid/ask spread can eat the whole effect.

Leader	Follower	Lag	ρ	Holdout ρ	Stability	Follower $/day	Tier
JSCP +211 more	TSEC	1d	+0.50	+0.35	100%	$120k	robust
NUBD +65 more	STBF	1d	+0.37	+0.27	100%	$184k	robust
WGMI +1 more	BCV	1d	+0.31	+0.27	88%	$290k	robust
SHY	CMBS	1d	+0.30	+0.23	88%	$1.6M	robust
DFNM	AFB	1d	+0.30	+0.32	75%	$813k	robust

All catch-up pairs →

Moves together

Strongest same-day co-movement. Near-identical funds are shown once.

Leader	Follower	ρ	Holdout ρ	Stability	Tier
OEF	SPY	+0.97	+0.97	100%	robust
ISPY	SPY	+0.97	+0.97	100%	robust
IJR	VIOG	+0.97	+0.95	100%	robust
AGG	AGGY	+0.97	+0.97	100%	robust
IWM	IWO	+0.97	+0.96	100%	robust
BKEM	EEM	+0.97	+0.98	100%	robust
FNDC	PDN	+0.97	+0.98	100%	robust
IWD	TVAL	+0.97	+0.95	100%	robust
REET	RWO	+0.97	+0.96	100%	robust
CEF	DBP	+0.97	+0.98	100%	robust
FTXO	IAT	+0.97	+0.97	100%	robust
HYG	SPHY	+0.97	+0.98	100%	robust
JEPQ	QQQ	+0.97	+0.96	100%	robust
QQQ	SEPQ	+0.97	+0.96	100%	robust
FWONA	FWONK	+0.97	+0.97	100%	robust

All same-day pairs →

Most followed

Symbols whose moves others most often repeat the next day.

#	Symbol	Influence	Followers	Top follower
1	SHY	1.02	3	TSEC
2	BSV	0.82	2	TSEC
3	BBBS	0.80	2	TSEC
4	IBTK	0.80	2	TSEC
5	JSCP	0.79	2	TSEC
6	IEI	0.79	2	TSEC
7	IBTJ	0.79	2	TSEC
8	IBTI	0.78	2	TSEC
9	SPMB	0.78	2	TSEC
10	BAMB	0.78	2	TSEC
11	ISTB	0.78	2	TSEC
12	AVSF	0.78	2	TSEC
13	SUSB	0.77	2	TSEC
14	BSCT	0.77	2	TSEC
15	IBDU	0.77	2	TSEC

All →

Moves opposite

Leader	Follower	ρ	Holdout ρ	Stability	Tier
CRSH	TSLA	-0.97	-0.99	100%	robust
DIPS	NVDA	-0.96	-0.98	100%	robust
FXE	UUP	-0.96	-0.95	100%	robust
ISHG	UUP	-0.95	-0.93	100%	robust
QQQ	YQQQ	-0.95	-0.97	100%	robust
SEPQ	YQQQ	-0.93	-0.94	100%	robust
VIXM	ZVOL	-0.93	-0.85	100%	robust
IWF	YQQQ	-0.92	-0.92	100%	robust
VXZ	ZVOL	-0.92	-0.84	100%	robust
SFY	YQQQ	-0.92	-0.94	100%	robust

Same exposure

Funds whose daily returns are near-identical (same-day ρ ≥ 0.97). Each group is listed under its most liquid member.

SPY ≈ VOO, IVV, VTI, SPYM, SCHX, IWB, ITOT, SCHB, DYNF, SPYI, VV +62 more
EFA ≈ IEFA, VEA, SCHF, SPDW, IDEV, AVDE, IQLT, DFAI, FENI, DFIC, ESGD +15 more
AGG ≈ IEF, BND, IUSB, BIV, FBND, JCPB, SPAB, SCHZ, BOND, DFCF, VCRB +8 more
IWF ≈ VUG, SPYG, IVW, MGK, VONG, VOOG, XLG, IWY, IUSG, JGRO, FELG +8 more
EEM ≈ IEMG, AVEM, AAXJ, DFAE, ESGE, DFEM, EMGF, XSOE, EEMA, GEM, JEMA +6 more
LQD ≈ VCIT, VCLT, IGIB, USIG, IGLB, SPLB, SPBO, QLTA, IGEB, CORP, VTC +6 more
QQQ ≈ QQQM, QQQI, GPIQ, ONEQ, QDTE, QTOP, QQH, IQQQ, QYLG, QQMG, QQQT +3 more
IBIT ≈ BITO, FBTC, GBTC, ARKB, BITB, BTC, HODL, BTCI, BTCO, EZBC, BRRR +2 more