An easy way is simply to track recent performance of an ETF such as MTUM, a periodically rebalanced (~6 months) ETF of high performing (mostly megacap) stocks. Here's a current (daily updated) table I use to monitor "momentum" and choose the highest recent average performing asset classes (aka GTAA).
QMOM rank = excluding 1m return, rank of average of 2m, 6m, 12m return
2-12 R - rank of return by product of (-2m rtn,-3m rtn,-4m rtn,...-12m rtn)
AVERAGE = Average of QMOM rank & 2-12 rank.

Pure US-only "momentum" (megacap tech) has the worst 1 month total return and is apparently decreasing momentum.

Emerging Markets and EAFE stocks have the best sustained and recent momentum, by far.

			                             QMOM rank	2-12 R	2-12RTN  1M	3M	6M	12M
				                               AVERAGE					
	iShares Core MSCI Emerging Markets	IEMG	1	1	1.262	5.59	8.23	19.81	33.22
	iShares MSCI EAFE Small Cap Index Fund	SCZ	2	2.0	1.238	4.56	10.11	11.49	29.40
	iShares MSCI EAFE Index Fund	        EFA	3	3.0	1.212	4.78	8.97	14.24	26.95
	Vanguard Global ex-U.S. Real Estate ETF	VNQI	7	5.5	1.146	4.55	4.41	4.57	19.79
	iShares MSCI USA Momentum ETF	        MTUM	7	6.0	1.137	-1.16	1.34	3.94	12.42
	SPDR S&P 500	                        SPY	6	6.0	1.129	0.16	2.00	9.34	13.10
	iShares S&P Small Cap 600 Growth ETF	IJT	5	6.0	1.056	5.27	8.93	14.36	9.05
	iShares Core S&P Small-Cap ETF	        IJR	4	6.0	1.050	6.67	11.32	19.33	12.01
	SPDR Barclays 1-3 Month T-Bill ETF	BIL	9	9.0	1.039	0.35	1.07	2.13	4.30
	Vanguard REIT	                        VNQ	10	10.0	0.981	4.24	3.33	2.73	1.22

FC