According to Morningstar's analysis of almost 3,000 mutual funds that hold U.S. and international stocks, "the median foreign large-blend fund had 109 holdings, compared to 67 holdings for the median large-blend fund in the United States." For funds holding small-cap stocks, the median for funds holding non-U.S. stocks was 98 stocks, with 67 for U.S. funds.

So the Harbor International Core Fund stands out, as it holds nearly eight times the average number of stocks in its portfolio at the end of June. And its annual turnover — the percentage rate of the portfolio's change over a one-year period — has been 123%, compared with a majority of the nearly 3,000 funds having turnover below 40%, according to Morningstar's study.

The median turnover for global large-cap funds was 28%. "Even the 75th percentile for turnover was in the 50%-range for some categories," according to the Morningstar analysts, who concluded that the data indicated that "a buy-and-hold approach is closer to the standard than the exception."

The $2.5 billion Harbor International Core Fund is rated five stars (the highest rating) within Morningstar's Large Foreign Blend fund category. Its performance benchmark is the MSCI EAFE Index. However, unlike the index, it can be as much as 15% allocated to stocks in emerging markets.

Gabriel McNerney, a managing director with Harbor Capital Advisors, which is based in Chicago, told MarketWatch how the fund's subadviser, Acadian Asset Management, uses a systematic process to manage the fund. Harbor partnered with Acadian to design and launch the fund in March 2019.

Using its quantitative model, the Acadian team analyzes companies' fundamentals, as well as stocks' price momentum patterns, analyst coverage, valuations and other technical factors. The daily analysis has evolved over the years to encompass "common suppliers, common customers," and even "which stocks are grouped together in passive vehicles," McNerney said.

"Everything is driven to look forward," he said, adding that Acadian was on its "41st model," as its quantitative analysis has expanded as markets have changed.

When asked how Acadian was incorporating artificial intelligence into its analysis, McNerney said one example was using natural-language processing as part of its analysis of peer groups. A stock's performance will depend on "how related companies (customers, or those in the supply chain, for example) perform," he said, adding that "machine learning helps identify those related companies. "

The analysis is also designed to incorporate macroeconomic events and even industry differences within countries. "Comparing an Indian and a Chinese bank — they are totally different," he said.

When asked why the Acadian team was holding so many stocks in the fund, McNerney stressed the importance of limiting downside risk. The daily quantitative process is designed to "come up with an alpha forecast for all 30,000 stocks, while limiting beta," he said. Alpha refers to how well a stock performs (or is expected to perform) relative to an index. Beta is a measure of volatility when compared with an index. A beta of 1 means the stock's volatility has matched the index's price volatility.

"We are not trying to increase returns at the expense of risk," McNerney said.

The fund was 23% concentrated to its largest 10 holdings as of June 30. McNerney said the 10 represented "our highest-conviction names," with that group concentrated in the pharmaceuticals and banking industries. This concentration at the top is offset by "a lot of little bets in the portfolio, which increases the chance of outperforming," he said.

Among the fund's largest holdings, McNerney cited Novartis NVS CH:NOVN as an example of a company scoring high among all the main drivers of the Acadian team's scoring. He said the pharmaceutical industry was benefiting from demographic factors and large international players "selling into the United States."

He also named ING Groep ING NL:INGA as an example that "you can get cheaper than Wells Fargo and cheaper than JPMorgan Chase, but it is growing faster than those banks."

Top holdings

Here are the largest 10 holdings of the Harbor International Core Fund as of June 30. Keep in mind that in the case of this particular fund, it is only a snapshot. The fund's top-10 holdings list may have changed significantly since it last disclosed its holdings. The fund tends to hold stocks as listed locally, although in some cases it holds an American depositary receipt traded in the U.S. So there are two columns of tickers — the fund's ticker and the U.S. ticker, which might be the same.

Performance against competing funds

For peer comparisons, LSEG calculates one-year total returns and average annual total returns for three-, five- and 10-year periods through the most recent month-end. The data provider lists 101 mutual funds as peers to the Harbor International Core Fund Fund that are also benchmarked to the MSCI EAFE Index, in U.S. dollars.

The Harbor International Core Fund Fund was established in 2019. After expenses, the fund's institutional share class has ranked eighth for one-year total return among the full group of peer funds. It has ranked second among the 102 funds for average three-year return and 13th for average five-year return.

The Harbor International Core Fund Fund's institutional shares have annual expenses totaling 0.85% of assets under management, which means $85 in annual fees for a $10,000 investment. So the fund's net expense ratio is 0.85%, but its full expense ratio is 0.94%. There is a temporary reimbursement of 0.09% of expenses until at least Feb. 28, 2027. There are other funds on the list below with temporary waivers of portions of their expenses. Before you make any investment, make sure you understand exactly how the expenses work and when any waivers might be lifted.

The following performance comparison begins with the Harbor International Core Fund Fund, then the iShares Core MSCI EAFE ETF. Then, since IEFA doesn't hold stocks in emerging markets and the Harbor fund can have exposure of up to 15% in EM, the next fund on the list is the iShares MSCI ACWI ex U.S. ETF ACWX. That is followed by the five peer funds whose shares are currently available for purchase, with the highest five-year annual returns. All returns are through July 31, include reinvested dividends and capital-gains distributions, and are net of expenses and net of any sales charges. The funds' net expense ratios are in the right-most column.

Click on the tickers for more about each company, fund or index.

Read: Tomi Kilgore's detailed guide to the information available on the MarketWatch quote page

Most of the share classes for mutual funds on this list are institutional share classes. This means they are distributed through investment advisers and might not be available through your brokerage account. Some (such as the Harbor fund's institutional shares) are available directly through some brokerage platforms. Account minimums may vary depending on the relationships between the fund manager or distributor and the advisory or brokerage firm.

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