Industrial stocks represent the fifth largest sector weight in the S&P 500, and the group has been an important driver of broader equity market returns in the U.S. this year. For example, the Industrial Select Sector SPDR (XLI), the largest exchange-traded fund (ETF) tracking the sector, is higher by 15.6% year to date. Investors have recently been displaying renewed enthusiasm for XLI, with that vigor coming on the back of a one-month gain of more than 5%.

"The fund has reeled in north of $1 billion just this month alone but year to date has attracted a net of only about $450 million (before the October inflows, the fund was actually in the red in terms of net year-to-date flows)," said Street One Financial Vice President Paul Weisbruch in a note out Monday. (See also: Industrials Sector: Industries Snapshot.)

XLI was one of several industrial ETFs to hit all-time highs on Monday following reports that Honeywell International Inc. (HON) is planning a corporate shake-up to unlock shareholder value. The company "plans to spin off non-core assets and create at least two new publicly listed companies, as the U.S. industrial conglomerate seeks to streamline its business," Reuters reported, citing sources familiar with the matter.

Honeywell is likely to retain its aerospace business, but the company's other footprints include "energy-efficient products and solutions for homes, specialty chemicals, electronic and advanced materials, and sensing, safety and security technologies for buildings, homes and industries," according to the Reuters article. New Jersey-based Honeywell is XLI's fourth largest holding, accounting for nearly 5% of the ETF's weight. (See also: Honeywell Spins Off Units Worth $7.5B in Sales, Keeps Aerospace.)

Speaking of the aerospace and defense industry, that has been the primary source of strength this year for diversified industrial ETFs such as XLI. Several of the best performing members of the Dow Jones Industrial Average this year are aerospace and defense stocks, namely The Boeing Company (BA), 3M Company (MMM) and United Technologies Corporation (UTX). That trio combines for about 16% of XLI's weight. Aerospace and defense is the largest industrial sub-sector in XLI, accounting for over one-quarter of the ETF's weight. In addition to XLI, several dedicated aerospace and defense ETFs hit record highs on Monday, cementing the status of those funds as among this year's best performing industry ETFs.

Industrial conglomerates and machinery makers combine for 36% of XLI's weight, while the ETF devotes over 21% of its weight to transportation-related stocks. (See also: Bet on Sector ETFs With Strong Beat Ratios.)

Want to learn how to invest?

Get a free 10 week email series that will teach you how to start investing.

Delivered twice a week, straight to your inbox.