If you are invested in stocks, it’s probably not a question of whether you have made money recently, only a matter of how much. As of June 30, the S&P 500 gained more than 15 percent in the previous 12 months, and has now risen higher for seven straight quarters.

One of the trends for much of this time was the unusually high correlation across companies and sectors. A rising economic tide lifted stocks at a surprisingly even pace, but that has changed dramatically in 2017.

A recent study by Nuveen Asset Management calculated the correlation between individual stocks to be at its lowest point in a decade. The performance gap has grown significantly this year when comparing stocks and equity sectors to one another, meaning the names you own and areas of the market you have exposure to have a greater impact on your returns.

In the first half of this year, the market’s best-performing equity sectors, technology and health care, gained more than 16 percent each. That’s more than double the return of the Dow and S&P 500 over the same period. The two worst-performing sectors, energy and telecom, both lost more than 10 percent.

A similar trend has taken place at the company level. Procter & Gamble, the world’s largest consumer staples company, gained 4 percent this year through June 30. Golden Valley-based General Mills lost 10 percent in that period. Investors can expect variation in stock returns even within the same sector, but it’s unusual to see such a huge gap in performance between global corporations that operate in the traditionally stable consumer goods business.

The lesson here is that investors should take inventory of their portfolio and understand where their exposure lies. This is equally important if you own mutual funds or index funds as opposed to individual stocks.

If you own a market-weighted S&P 500 index fund, more than 23 percent of that money is invested in tech stocks. And a full 10 percent of the index is in four companies (Apple, Microsoft, Amazon, and Facebook).

Tech stocks have performed exceptionally well this year. However, many of those are high-valuation companies and will be especially vulnerable in a market correction. If you are in an index fund, note that a growing percentage of those dollars are being invested in the sectors or companies trading at all-time highs.

By revisiting what you own, investors can be better prepared for the day when market conditions become less favorable. 

Ben Marks is the chief investment officer at Marks Group Wealth Management in Minnetonka.