v3.26.1
Shareholder Report
6 Months Ended
Jun. 30, 2026
USD ($)
Holding
Shareholder Report [Line Items]  
Document Type N-CSRS
Amendment Flag false
Registrant Name FORUM FUNDS
Entity Central Index Key 0000315774
Entity Investment Company Type N-1A
Document Period End Date Jun. 30, 2026
C000012470  
Shareholder Report [Line Items]  
Fund Name Polaris Global Value Fund
Trading Symbol PGVFX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Polaris Global Value Fund for the period of January 1, 2026, to June 30, 2026.
Shareholder Report Annual or Semi-Annual Semi-Annual Shareholder Report
Additional Information [Text Block]

This semi-annual shareholder report contains important information about the Polaris Global Value Fund for the period of January 1, 2026, to June 30, 2026. You can find additional information about the Fund at https://polarisfunds.com/resources/. You can also request this information by contacting us at (888) 263-5594.

Additional Information Phone Number (888) 263-5594
Additional Information Website https://polarisfunds.com/resources/
Expenses [Text Block]

What were the Fund's costs for the last six months

(based on a hypothetical $10,000 investment)

Table Summary
Fund Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Polaris Global Value Fund
$54
0.99%
Expenses Paid, Amount $ 54
Expense Ratio, Percent 0.99%
Factors Affecting Performance [Text Block]

How did the Fund perform in the last six months

The Fund outperformed the benchmark, with outsized gains in information technology, followed by double-digit returns in health care, energy, materials and utilities. Consumer sectors were underwhelming, as was communication services. Geographically, the Fund capitalized on its off-benchmark IT holdings in South Korea, while exacting heady gains in the United States, Canada, Ireland and a handful of other countries; China was the most notable detractor.

 

SK hynix and Samsung Electronics rode demand for commodity and high bandwidth memory (HBM) chips. SK hynix sold out its 2026 HBM capacity and joined the $1 trillion market cap club; in June its shares surged after announcing Nasdaq ADR plans. MKS Inc. and Arrow Electronics posted strong results; Arrow authorized a $1 billion buyback, while MKS rallied on robust earnings and a pre announced second quarter beat, reaching our target and prompting a profitable exit.

 

Among other top contributors: Financial institution Popular Inc. rose on higher earnings expectations and a more supportive local rate outlook, confident that an eventual easing in U.S./Puerto Rico rates would lower funding costs. In health care, Lantheus Holdings Inc. reported strong quarterly earnings, the FDA approval of PYLARIFY TruVu and intensified M&A interest.

 

In consumer discretionary, Alibaba Group Holding confronted multiple headwinds including a U.S. military blacklist, acquisition target concerns, and distillation allegations from Anthropic that could invite U.S. sanctions. Sony Group Corp. faced memory chip price spikes that threatened PlayStation 5 margins and the delayed release of popular software titles. A few financials were also middling: Ping An Insurance Group underperformed as a proxy for China macro pessimism, while Capital One Financial fell after earnings missed consensus estimates, with net income declining year over year largely due to Discover acquisition costs.

Top Contributors

Top Detractors

  • Thin up arrow

    SK hynix Inc.

  • Thin up arrow

    Samsung Electronics

  • Thin up arrow

    MKS Inc.

  • Thin up arrow

    Arrow Electronics Inc.

  • Thin up arrow

    Lantheus Holdings Inc.

 

  • Thin down arrow

    Adobe Inc.

  • Thin down arrow

    Sony Group Corp.

  • Thin down arrow

    Alibaba Group Holding Ltd.

  • Thin down arrow

    Capgemini SE

  • Thin down arrow

    Astor Transformator Enerji

Performance Past Does Not Indicate Future [Text] The Fund’s past performance is not a good predictor of how the Fund will perform in the future.
Line Graph [Table Text Block]
Growth of 10K Chart
Table Summary
Date
Polaris Global Value Fund
MSCI World Index
06/30/16
$10,000
$10,000
09/30/16
$10,917
$10,487
12/31/16
$11,465
$10,681
03/31/17
$12,010
$11,362
06/30/17
$12,635
$11,820
09/30/17
$13,107
$12,391
12/31/17
$13,827
$13,074
03/31/18
$13,482
$12,906
06/30/18
$13,662
$13,130
09/30/18
$13,897
$13,784
12/31/18
$12,077
$11,935
03/31/19
$13,330
$13,424
06/30/19
$13,753
$13,961
09/30/19
$13,593
$14,036
12/31/19
$14,830
$15,237
03/31/20
$10,122
$12,029
06/30/20
$12,010
$14,358
09/30/20
$12,535
$15,497
12/31/20
$15,816
$17,660
03/31/21
$17,538
$18,529
06/30/21
$18,011
$19,964
09/30/21
$17,821
$19,963
12/31/21
$18,251
$21,513
03/31/22
$17,408
$20,405
06/30/22
$15,156
$17,102
09/30/22
$13,753
$16,044
12/31/22
$16,058
$17,610
03/31/23
$16,509
$18,972
06/30/23
$16,790
$20,267
09/30/23
$16,415
$19,566
12/31/23
$18,430
$21,799
03/31/24
$19,519
$23,735
06/30/24
$19,329
$24,360
09/30/24
$20,621
$25,910
12/31/24
$19,413
$25,869
03/31/25
$20,192
$25,406
06/30/25
$21,964
$28,320
09/30/25
$23,063
$30,379
12/31/25
$24,648
$31,326
03/31/26
$26,063
$30,207
06/30/26
$29,607
$34,363
Average Annual Return [Table Text Block]
Table Summary
 
One Year
Five Year
Ten Year
Polaris Global Value Fund
34.80%
10.45%
11.47%
MSCI World Index
21.34%
11.47%
13.14%
No Deduction of Taxes [Text Block] The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund shares.
Performance Table Market Index Changed [Text Block]  
Updated Performance Information Location [Text Block] Updated performance can be found at www.polarisfunds.com/performance.
AssetsNet $ 574,941,069
Holdings Count | Holding 88
Advisory Fees Paid, Amount $ 2,114,082
InvestmentCompanyPortfolioTurnover 14.00%
Additional Fund Statistics [Text Block]

Fund Statistics

Table Summary
Total Net Assets
$574,941,069
# of Portfolio Holdings
88
Portfolio Turnover Rate
14%
Investment Advisory Fees (Net of fees waived)
$2,114,082
Holdings [Text Block]

Country Weightings 

(% total investments)*

Group By Country Chart
Table Summary
Value
Value
United States
34.2%
South Korea
13.5%
Japan
9.4%
France
5.6%
Germany
5.0%
United Kingdom
4.9%
Ireland
4.8%
Italy
3.5%
Norway
3.0%
Switzerland
2.4%
Spain
2.1%
Puerto Rico
1.6%
China
1.5%
Chile
1.4%
Turkey
1.2%
Singapore
1.1%
Netherlands
1.1%
Sweden
1.1%
Hong Kong
0.9%
Taiwan
0.7%
Canada
0.5%
Belgium
0.5%
Russia
0.0%

* excluding cash equivalents

Sector Weightings

(% total investments)*

Group By Sector Chart
Table Summary
Value
Value
Financials
25.6%
Industrials
15.7%
Information Technology
15.2%
Health Care
14.1%
Consumer Discretionary
8.3%
Energy
5.2%
Materials
4.9%
Consumer Staples
4.8%
Communication Services
2.8%
Utilities
2.5%
Real Estate
0.9%

* excluding cash equivalents

Largest Holdings [Text Block]

Top Ten Holdings 

(% total investments)*

Table Summary
SK hynix, Inc.
5.63%
Samsung Electronics Co., Ltd.
5.14%
Lantheus Holdings, Inc.
2.21%
United Therapeutics Corp.
2.06%
Arrow Electronics, Inc.
1.88%
CVS Health Corp.
1.70%
Marathon Petroleum Corp.
1.66%
Popular, Inc.
1.61%
International Consolidated Airlines Group SA
1.59%
Shinhan Financial Group Co., Ltd.
1.57%

* excluding cash equivalents