The table below describes the fees and expenses that you may pay if you buy, hold, and sell the Fund’s Class I Shares and Retail Class Shares. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and expense example below. As of the date of this Prospectus, Retail Class Shares are not operational.

Shareholder Fees, Caption

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Shareholder Fees

Operating Expenses, Caption

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Annual Fund Operating Expenses

Portfolio Turnover, Heading

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Portfolio Turnover

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The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example above, affect the Fund’s performance. For the period from May 24, 2021 (the Fund’s commencement of operations) to October 31, 2021, the Fund’s portfolio turnover rate was 3% of the average value of its portfolio.

Portfolio Turnover, Rate

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3.00%

Other Expenses, New Fund, Based on Estimates [Text]

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Other Expenses for Retail Class Shares are based on estimated amounts for the current fiscal year.

Expense Example, Heading

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EXAMPLE

Expense Example, Narrative

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This example is intended to help you compare the cost of investing in the Fund’s Class I Shares and Retail Class Shares to the cost of investing in other mutual funds. This example gives effect to the Expense Limitation Agreement for 1 year and the first year of the 3-year calculations. The example assumes that you invest $10,000 in the Fund’s Class I Shares and Retail Class Shares for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the operating expenses of the Fund’s Class I Shares and Retail Class Shares remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Investment Strategy, Heading

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PRINCIPAL INVESTMENT STRATEGIES

Investment Strategy, Narrative

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Under normal circumstances, the Fund invests at least 80% of its net assets, plus the amount of any borrowings for investment purposes, in mid capitalization (mid cap) publicly traded equity securities. Domestic securities include companies that are incorporated or headquartered in the U.S. Such securities may be issued by domestic or foreign issuers. The Fund may invest in the securities of foreign issuers both directly and in the form of depository receipts, including both sponsored and unsponsored American Depository Receipts (“ADRs”) and Global Depository Receipts (“GDRs”), each of which represent an interest in foreign securities. Securities of foreign issuers, or foreign securities, include companies that are neither incorporated nor headquartered in the U.S. The Fund primarily seeks to buy common stock and may also invest in preferred stock. The Fund may also invest in large cap and small cap publicly traded equity securities. From time to time the Fund may invest in shares of companies through “new issues” or initial public offerings (“IPOs”). Subject to applicable statutory and regulatory limitations, the Fund may invest in shares of other investment companies, consisting of mutual funds and exchange-traded funds (“ETFs”). The Fund may also purchase other securities with equity characteristics, including securities convertible into common stock. Brown Brothers Harriman & Co. (“BBH&Co.”), through a separately identifiable department (“Investment Adviser”), considers mid cap securities to be securities that at the time of purchase have a market capitalization within the range of companies

included in the Russell Midcap Index. As of January 31, 2022, the market capitalization range of companies included in the Russell Midcap Index was $720.0 million to $62.3 billion.

The Fund’s strategy is based on fundamental business analysis and a long-term orientation. The Investment Adviser selects companies based on their qualitative merits, competitive profile and prospective value creation potential. As part of the Fund’s investment process, the Investment Adviser considers environmental, social and governance (“ESG”) factors for each investment in the portfolio. ESG factors include, but are not limited to, the environmental and social impact of the issuer, as well as the issuer’s instituted governance programs. The Fund follows a “buy and own” approach that does not make use of short-term trades in pursuit of small gains. The Investment Adviser believes that its long-term orientation can benefit the Fund’s net performance results. Investments may be sold if they appreciate to levels at or near the higher end of the Investment Adviser’s estimated ranges of intrinsic value.

The Fund is non-diversified and may invest a greater percentage of its assets in a particular issuer than would a diversified fund.

Strategy Portfolio Concentration

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Risk, Heading

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PRINCIPAL RISKS OF THE FUND

Risk, Narrative

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The principal risks of investing in the Fund and the circumstances reasonably likely to adversely affect an investment are listed and described below. The share price of the Fund changes daily, based on market conditions and other factors. A shareholder may lose money by investing

in the Fund. There can be no assurance that the Fund will achieve its investment objective.

Mid Cap Company Risk:

Mid cap companies, when compared to larger companies, may experience lower trade volume and could be subject to greater and less predictable price changes. Mid cap companies may also have limited management experience or depth, limited ability to generate or borrow capital needed for growth, limited products or services, or operate in less established markets. Therefore, mid cap securities may be subject to changing economic, market, and industry conditions and experience more volatility and less liquidity over short periods.

Investment Risk:

Investors in the Fund could lose money, including the possible loss of the entire principal amount of an investment, over short or long periods of time.

Market Risk:

The price of a security may fall due to changing economic, political, regulatory or market conditions, or due to a company’s or issuer’s individual situation. Natural disasters, the spread of infectious illness and other public health emergencies, recession, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse effects on world economies and markets generally.

Equity Securities Risk:

Equity securities risk is the risk that prices of equity securities rise and fall daily. Price movements may occur due to factors affecting individual companies, such as the issuance of an unfavorable earnings report, or other events affecting particular industries or the equity market as a whole.

Non-Diversification Risk:

Because a non-diversified fund under the federal securities laws may invest in a relatively small number of issuers compared to a diversified fund, changes in the financial condition of individual issuers, as well as political, regulatory or economic occurrences affecting such issuers may cause greater fluctuation in the value of a non-diversified fund’s shares. However, the Fund intends to satisfy the asset diversification requirements for qualification as a regulated investment company (a “RIC”) under Subchapter M of the Internal Revenue Code of 1986, as amended (the “Code”).

Large Shareholder Risk:

Asset allocation decisions, particularly large redemptions, made by an investor or an investment adviser whose discretionary clients make up a large percentage of the Fund’s shareholders, may adversely impact remaining Fund shareholders.

Management Risk:

The Fund is actively managed, and its success depends upon the investment skills and analytical abilities of the Investment Adviser to develop and effectively implement strategies that achieve the Fund’s investment objective. Subjective decisions made by the Investment Adviser may cause the Fund to incur losses or to miss profit opportunities on which it may otherwise have capitalized.

Large Cap Company Risk:

Because the Fund may invest in large cap company securities, it may underperform other funds during periods when the Fund’s large cap securities are out of favor.

Small Cap Company Risk:

Small cap companies may have limited product lines or markets. They may be less financially secure than larger, more established companies and may depend on a more limited management group than larger capitalized companies.

Foreign Investment Risk:

Investing in securities of foreign-based companies, including sponsored and unsponsored ADRs and GDRs, involves risks not typically associated with investing in securities of companies organized and operated in the United States. These risks include adverse political, social and economic developments abroad, different kinds and levels of market and issuer regulations, and the different characteristics of overseas economies and markets. These factors can make foreign investments more volatile and potentially less liquid than U.S. investments. Additionally, investments in foreign securities may be denominated in currencies, other than the U.S. dollar, which are subject to changes in currency exchange rates. These fluctuations could offset investment gains or add to investment losses. Unsponsored ADRs do not trade on an exchange and therefore may be difficult to sell and investors do not have the benefits and voting rights that are extended to other shareholders.

Investment in Other Investment Companies Risk:

Investments in other investment companies are subject to market and selection risk, as well as the specific risks associated with the investment companies' portfolio securities. As a shareholder of another investment company, the Fund would bear, along with other shareholders, its pro rata portion of the other investment company's expenses, including advisory fees.

The shares of an investment company that trade on an exchange (for example, an ETF) may trade below their net asset value or at a discount, which may adversely affect the Fund's performance.

IPO Risk:

IPOs are new issues of equity securities. Securities issued in IPOs have no trading history, and information about the companies may be available for very limited periods. In addition, the prices of securities sold in IPOs may be highly volatile or may decline shortly after the IPO.

Preferred Securities Risk:

The Fund may invest in preferred securities, which are equity interests in a company that entitle the holder to receive common stock, dividends and a fixed share of the proceeds resulting from a liquidation of the company, in preference to the holders of other securities. Preferred securities may pay fixed or adjustable rates of return. Preferred securities are subject to issuer-specific and market risks applicable generally to equity securities. In addition, a company’s preferred securities generally pay dividends only after the company makes required payments to holders of its bonds and other debt. If a company experiences actual or perceived changes in its financial condition or prospects, the value of preferred securities may be more greatly affected than the value of bonds and other debt.

FUND PERFORMANCE

Risk, Lose Money

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A shareholder may lose money by investing

Risk, Nondiversified Status

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Non-Diversification Risk: Because a non-diversified fund under the federal securities laws may invest in a relatively small number of issuers compared to a diversified fund, changes in the financial condition of individual issuers, as well as political, regulatory or economic occurrences affecting such issuers may cause greater fluctuation in the value of a non-diversified fund’s shares. However, the Fund intends to satisfy the asset diversification requirements for qualification as a regulated investment company (a “RIC”) under Subchapter M of the Internal Revenue Code of 1986, as amended (the “Code”).

Bar Chart and Performance Table, Heading

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FUND PERFORMANCE

Performance, Narrative

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The Fund commenced investment operations on May 24, 2021 and, therefore, does not have performance history for a full calendar year. Once the Fund has completed a full calendar year of operations, performance information will be indicative of the risks of investing in the Fund by comparing the Fund’s performance relative to the Fund’s benchmark index and peer group.

Performance One Year or Less [Text]

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BBH Select Series - Mid Cap Fund | Class I Shares

Risk/Return:

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Maximum Sales Charge (Load) Imposed on Purchases

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none

Maximum Deferred Sales Charge (Load)

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none

Maximum Sales Charge (Load) Imposed on Reinvested Dividends

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none

Redemption Fee on shares held less than 30 days after purchase (as a percentage of amount redeemed, if applicable)

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2.00%

Exchange Fee

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none

Management Fees

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0.75%

Distribution (12b-1) Fees

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none

Other Expenses

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1.71%

^[1]

Total Annual Fund Operating Expenses

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2.46%

Less Fee Waiver/Expense Reimbursement

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(1.56%)

^[2]

Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement

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0.90%

Fee Waiver or Reimbursement over Assets, Date of Termination

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March 1, 2023

1 Year

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$ 92

3 Years

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617

5 Years

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1,170

10 Years

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$ 2,678

BBH Select Series - Mid Cap Fund | Retail Class Shares

Risk/Return:

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Maximum Sales Charge (Load) Imposed on Purchases

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none

Maximum Deferred Sales Charge (Load)

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none

Maximum Sales Charge (Load) Imposed on Reinvested Dividends

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none

Redemption Fee on shares held less than 30 days after purchase (as a percentage of amount redeemed, if applicable)

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2.00%

Exchange Fee

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none

Management Fees

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0.75%

Distribution (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other Expenses

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1.71%

^[1]

Total Annual Fund Operating Expenses

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2.71%

Less Fee Waiver/Expense Reimbursement

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(1.56%)

^[2]

Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement

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1.15%

Fee Waiver or Reimbursement over Assets, Date of Termination

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March 1, 2023

1 Year

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$ 117

3 Years

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$ 693

[1]

Other Expenses for Retail Class Shares are based on estimated amounts for the current fiscal year.

[2]

Brown Brothers Harriman & Co., through a separately identifiable department has contractually agreed to limit Total Annual Fund Operating Expenses of Class I Shares and Retail Class Shares to 0.90% through March 1, 2023 (excluding interest, taxes, brokerage commissions, and other expenditures that are capitalized in accordance with generally accepted accounting principles, and other extraordinary expenses not incurred in the ordinary course of the Fund’s business, and amounts payable pursuant to any plan adopted in accordance with Rule 12b-1 under the Investment Company Act of 1940 (the “1940 Act”)) (the “Expense Limitation Agreement”). Because Rule 12b-1 fees are excluded from the expense limit, total operating expenses after waiver/reimbursement for Retail Class Shares of the Fund are 1.15% of the average daily net assets, as shown above. The Expense Limitation Agreement may only be terminated during its term with approval of the Fund’s Board of Trustees (the “Board”).