The stock market just did something it last did in 1978. History says this will happen next.

The Dow Jones Industrial Average (^DJI 0.48%)one of three major US stock market indexes, had fallen for nine consecutive trading sessions as of Tuesday, December 17. The last time the Dow Jones put together such a long losing streak was February 1978.

Specifically, the index fell more than 4% during the nine trading days ending February 22, 1978. But the Dow Jones gained 14% over the next three months and gained 20% over the next six months. Investors expecting a similar result this time around can gain exposure SPDR Dow Jones Industrial Average ETF Trust (DIA 0.54%).

Here’s the case for owning a Dow Jones exchange-traded fund (ETF) right now.

The Bull case: Dow Jones tracks 30 blue chip companies

The Dow Jones Industrial Average is the oldest of the three most popular US stock market indices. It was first introduced in May 1896, but tracked only 12 industrial stocks at that time. The index has evolved to include 30 companies from nine of the 11 market sectors. The two sectors not represented are utilities and real estate.

Dow Jones is not governed by specific inclusion criteria, but the selection committee tends to choose stocks with three characteristics: excellent reputation, sustained earnings growth and widespread investor interest. To that end, the Dow Jones is often seen as a benchmark for blue chip (high quality) value stocks.

The SPDR Dow Jones Industrial Average ETF Trust tracks the performance of the Dow Jones. The ETF lets investors diversify capital across 30 high-quality companies that play a central role in driving the US economy. The top 10 holdings are listed by weight below:

1. Goldman Sachs: 8.2%
2. UnitedHealth Group: 6.9%
3. Microsoft: 6.3%
4. Home Depot: 5.7%
5. Caterpillar: 5.3%
6. Sherwin Williams: 5.1%
7. Salesforce: 5%
8. Visa: 4.4%
9. American Express: 4.2%
10. McDonald’s: 4.1%

The last consequence item is the cost percentage. The SPDR Dow Jones Industrial Average ETF Trust has a below-average expense ratio of 0.16%. That means investors pay $16 a year in fees for every $10,000 invested in the ETF.

The Bear Case: The Dow Jones has consistently underperformed the S&P 500

The Dow Jones returned 151% over the past decade, or 9.6% annually. Meanwhile S&P 500 advanced 200%, compounded at 11.6% annually. The exact same pattern shows up over the last one, three and five years. In other words, the Dow Jones has consistently underperformed the S&P 500.

In addition, the Dow Jones is currently trading at a premium relative to its expected growth. Specifically, its constituent companies are expected to collectively grow earnings by 11.3% annually over the next three to five years. Dividing that number into its current valuation of 21.1 times earnings yields a price-to-earnings-to-growth (PEG) ratio of 1.9. It is relatively expensive.

By comparison, S&P 500 companies collectively are expected to report earnings growth of 15.1% annually over the same period. Dividing that number by its current valuation of 24.7 times earnings yields a PEG ratio of 1.6. That metric isn’t cheap, but it’s cheaper than the Dow Jones PEG ratio.

Here’s the bottom line: History says the Dow Jones could rise sharply in the coming weeks and months. But the index has historically underperformed the S&P 500 and has a higher valuation.

To that end, I’m in no rush to add a Dow Jones ETF to my portfolio. In fact, I would buy an S&P 500 ETF before a Dow Jones ETF without thinking twice.