Foreign stocks represent an attractive option for investors who wish to diversify their portfolios, with brokers ready to assist in these foreign investments. Still, it's worth noting these international index funds carry their own special risks, ranging from currency-related to political, and can pose liquidity and due diligence problems for retail investors. Index funds that are global in scope and follow a passive investment approach provide cost-effective means of investing overseas. Here are four of the best international index funds. All info is current as of May 2020.

Fidelity International Index Fund (FSPSX)

Assets under management (AUM): $25.5 billion

Net asset value (NAV): $39.08

Net expense ratio: 0.035%

The Fidelity International Index Fund tracks the performance of the MSCI Europe, Australasia, Far East Index (EAFE), which is a broad index that represents the performance of foreign developed-market stocks. The fund uses sampling techniques to attain investment results similar to those of the underlying index. European stocks have the largest allocation at 61%, while Japanese equities account for about 25% of the fund's assets. The fund provides large exposure to financial and industrial stocks, which have 15.72% and 14.19% allocations respectively. The fund's portfolio is widely diversified; its top 10 holdings account for only about 12.55% of its assets.

The Fidelity International Index Fund offers a diversified international portfolio at a very low cost. Because the fund avoids emerging market equities, its returns are subject to lower volatility. Morningstar has awarded the fund a silver analyst rating and a four-star overall rating. 

Schwab International Index Fund (SWISX)

AUM: $5.9 billion

NAV: $18.85

Net expense ratio: 0.06%

The Schwab International Index Fund also seeks to track the performance of the MSCI EAFE Index. While European and Japanese companies line the top of this fund's portfolio, approximately 16% are invested in the financial services sector while 15% follow in healthcare, and a little under 15% in industrials. Like other international equity stocks, the fund exposes investors to foreign currency fluctuations.

The fund has one of the lowest net expense ratios among its peers and an exceptionally low turnover ratio of 5%, making it highly tax efficient. Morningstar has awarded the fund a bronze analyst rating and a four-star overall rating. The fund has no load fees and comes with a minimum investment requirement of just $1. 

Pax MSCI EAFE ESG Leaders Index Fund (PXINX)

AUM: $568 million

NAV: $8.83

Net expense ratio: 0.74%

The Pax MSCI EAFE ESG Leaders Index Fund (formerly the MSCI International ESG Index Fund) tracks the performance of the MSCI EAFE ESG Index, which is a member of the MSCI Global Sustainability Indexes. The index provides exposure to companies with high environmental, social and governance performances relative to their sector peers. The fund's portfolio consists of a mixture of large- and mid-cap foreign stocks with a high geographical concentration in Japan--approximately 26.4% of assets. About 16.1% of the fund's assets are allocated each to financial stocks and industrials, while health care equities have a 14.4% allocation.

Morningstar has given the fund a four-star overall rating based on its institutional class. The fund does not charge load fees and comes with a minimum investment requirement of $1,000.

Vanguard Developed Markets Index Fund Admiral Shares (VTMGX)

AUM: $111.9 billion

NAV: $12.83

Net expense ratio: 0.07%

The Vanguard Developed Markets Index Fund tracks the performance of a benchmark index that measures the investment return of stocks issued by companies located in Canada and the major markets of Europe and the Pacific region. In 2014, Vanguard merged two of its foreign equity funds to form the Vanguard Developed Markets Index Fund. The fund has an exceptionally low turnover ratio of 2.4%, making this fund highly tax-efficient for its investors. The fund mainly invests in large- and mid-cap stocks of developed markets; 22.8% of its assets are in Japan, followed by 12.63% in the United Kingdom and 8.44% in Canada.

For its very low expense ratio, consistent management and return, the fund has earned a gold analyst rating and a four-star overall rating from Morningstar. The fund charges no load fees and requires its investors to contribute at least $3,000.