ETF as the universe

Can I use a specific ETF as my universe, or a combination of multiple ETFs as my universe?

Thanks
Tony

I assume you want a stock universe to emulate the holdings for a specific ETF or group of ETFs.

In this article with links are the rules to set up universes to emulate the historic holdings of:

The Technology Select Sector SPDR Fund (XLK) (article-1);
The Consumer Staples Select Sector SPDR Fund (XLP) (article-2);
The Healthcare Select Sector SPDR Fund (XLV) (article-3);
The Industrial Select Sector SPDR Fund (XLI) (article-4);
The Utility Select Sector SPDR Fund (XLU) (article-5);
The Materials Select Sector SPDR Fund (XLB) (article-6); and
The Consumer Discretionary Select Sector SPDR Fund (XLY) (article-7) .

https://imarketsignals.com/2020/profiting-from-trading-the-stocks-of-the-invesco-qqq-trust-im-top5qqqselect/

Very good. Got one for an energy ETF, like XES?

No, I concentrated on sector ETFs except for Financials and Energy.
If you come up with something useful for XES then please post universe rules here.

EDIT: Why would one want to invest in XES with a max D/S of -95%.

Sectors are rotating to both energy and financials right now.