The bull market run is ripe with thriving companies that give investors opportunities to invest in momentum. After all, stocks have been tapping all-time highs. But today’s market does have some pockets of struggling industries, and some analysts have recently called for a more significant selloff in the months ahead. Relevant roadblocks to a continued bull run in the last five months of 2018 include the U.S and China trade dispute; the recent battering of significant tech leaders such as Facebook and Netflix; and the mixed outlook for energy prices, currently at 3-year highs.

All of which highlights the need to keep an eye on potential areas of the market that an investor can potentially short.

Here are three sectors to explore shorts for 2018:

Independent Oil and Gas 

Like many commodities, the oil and gas business is cyclical, and it’s been in a down cycle amid a glut of global supply. The price of oil began to stabilize and recover between the second half of 2017 and January 2018, where it hit more than 3-year highs of $70 per barrel. Since then, it's churned in a narrow range, with Brent crude standing at just under $73 per barrel as of August 8, 2018, near the 3-year highs but still significantly lower than $115 per barrel, the post-recession high hit in March 2011. U.S. light crude oil prices have been under pressure lately as well, falling to 7-week lows of just under $67 per barrel as of August 8, 2018. Concerns about the U.S.-China trade dispute have weighed heavily on commodity prices.

The outlook for oil and gas over the next few years remains mixed. The recent price increase has coincided with expectations of stronger demand in 2018 and commitments from OPEC and other allies to extend production cuts, which should be supportive for prices. But the U.S. is not expected to follow suit with production cuts, with U.S. shale production likely to rise. That, paired with geopolitical risk, could limit any gains.

The U.S. Energy Information Administration (EIA) is forecasting that Brent crude oil spot price will average $72 per barrel in 2018 and $71 per barrel in 2019, according to the newest forecasts, released August 7, 2018. West Texas Intermediate (WTI) crude oil prices are expected to average about $66 per barrel in 2018 and $67 per barrel in 2019. The EIA is also forecasting that U.S. crude oil production will average 10.7 million barrels per day in 2018, up from 9.4 million in 2017; forecasts for 2019 are 11.7 million barrels per day.

Independent oil-related companies like Superior Energy Services (SPN​) are struggling and are likely to continue to struggle if oil prices remain choppy. That’s because they tend to have higher-than-average costs. Superior shares lost 44 percent in 2017 and have lost another 8 percent so far in 2018.

Traditional and Apparel Retailers

The overall improved economic environment and impact from the tax cuts seem to be supporting a better overall retail environment and an increase in consumer spending this year. Gross Domestic Product (GDP) grew at a better-than-expected 4.1% rate in the second quarter, marking the fastest pace of growth in over four years, the government recently reported. But the corresponding improvement in consumer spending has been more supportive of e-commerce and big home improvement stores like Home Depot, with traditional and clothing retailers seeing less of a benefit.

Moody's said it sees select weakness in apparel and footwear, auto retailers and office supply stores, among others. Retailers with a heavy presence in malls have been especially hurt by today’s move online. A slew of mall-based apparel retailers filed for bankruptcy last year, including Gymboree, Wet Seal, The Limited, and BCBG Max Azria. That weakness has impacted the department stores chains that anchor malls, like JC Penney (JCP​) and Macy’s (M), both of which had a rough time in 2017. But the agency says it sees losses tapering off for such companies in the next few years.

U.S. retail sales increased by 0.5% in June, from an upwardly revised 1.3% gain in May, the Commerce Department reported. June sales are the most recently available figures. Sales were driven mostly by automobiles and gas prices. So-called "core" sales, which exclude volatile food and energy prices, were unchanged in June versus an upwardly revised rise of 0.8% in May.

Retail Real Estate

Potential weakness can also be found in the companies related to the real estate supported by retailers.

Mall landlords or real estate investment trusts (REITs), including Simon Property Group (SPG), are feeling the brunt of the ailing retail sector’s bankruptcies and store closures. For example, Sears Holdings (SHLD) recently announced it would close another 63 locations in 2018.

Without retail tenants, mall landlords can’t collect rent. Their problems will likely continue to escalate as more traditional retailers with sliding sales shutter stores and break leases under bankruptcy protection. Simon Property Group's stock is down about 11 percent over the last year. Shares of DDR Corp. have fallen about 49 percent in the same period.