Strategy. The Fund is primarily managed as a fund that invests in other funds (i.e., a fund-of-funds) that seeks to achieve its investment objective by investing its assets among a selected group of underlying stock and bond mutual funds and exchanged-traded funds (ETFs) for which Columbia Wanger Asset Management, LLC, the Funds investment adviser (the Investment Manager) or its affiliates, including Columbia Management Investment Advisers, LLC (Columbia Management), serves as investment adviser or principal underwriter ( collectively, the Portfolio Funds). Under normal circumstances, the Fund allocates at least 95% of its net assets (stock/bond assets) among the Portfolio Funds according to an asset allocation table based on the current level of the Standard & Poors (S&P) 500 Index. Generally, the Funds … Show more… The Fund is primarily managed as a fund that invests in other funds (i.e., a fund-of-funds) that seeks to achieve its investment objective by investing its assets among a selected group of underlying stock and bond mutual funds and exchanged-traded funds (ETFs) for which Columbia Wanger Asset Management, LLC, the Funds investment adviser (the Investment Manager) or its affiliates, including Columbia Management Investment Advisers, LLC (Columbia Management), serves as investment adviser or principal underwriter ( collectively, the Portfolio Funds). Under normal circumstances, the Fund allocates at least 95% of its net assets (stock/bond assets) among the Portfolio Funds according to an asset allocation table based on the current level of the Standard & Poors (S&P) 500 Index. Generally, the Funds allocation to stock funds increases as the S&P 500 Index declines and decreases as the S&P 500 Index rises. When the S&P 500 Index goes up in relation to trading range bands that are predetermined by the Investment Manager, the Fund sells a portion of its stock Portfolio Funds and invests more in the bond Portfolio Funds, and when the S&P 500 Index goes down in relation to the predetermined bands, the Fund increases its investment in the stock Portfolio Funds. Under normal circumstances, the Fund may invest up to 5% of net assets plus any cash received that day in cash, high quality short-term paper and government securities. Although many asset allocation funds follow a basic approach of moving assets from stocks to bonds when the equity market goes up, and from bonds to stocks when the equity market goes down, some are run by investment managers who allocate fund assets by making subjective decisions based on complicated economic and financial models and complex graphs of market behavior. By contrast, the day-to-day investment decisions for the Fund are made according to a single predetermined allocation table. The temperature in your house is run by a single rule: your thermostat turns on the furnace if your house is too cold or turns on the air conditioner if your house is too warm. This Fund works the same way, so it is named Columbia Thermostat Fund. Just as a thermostat may be set at different ranges for different seasons, the structure and allocation ranges of the Funds asset allocation table may be changed from time to time between two forms, based on the Investment Managers determination of whether it expects the equity market to be moving over the next year in a side-ways or non-directional pattern, which the Investment Manager terms an expensive market, or to be trending upward, which the Investment Manager terms a normal market. The Investment Managers process and methodology for determining whether the current market is expensive or normal and the structure of each form of allocation table are described in more detail in the Principal Investment Strategies section of the Fund's statutory prospectus. Such determination will be made on at least an annual basis and will be reflected in the asset allocation table disclosed in the Funds statutory prospectus. In general, the two different forms of allocation table are intended to maximize the capture of value under the two different sets of market conditions. The Funds current form of asset allocation table, which is set forth in the Principal Investment Strategies section of the Fund's statutory prospectus, has been in place since the Funds inception, except for the period from May 1, 2020 through April 30, 2021. The current form of asset allocation table reflects the Investment Managers determination that the equity market is currently expensive. The expensive form of table may result in equity investment allocations as low as 10% or as high as 90% of Fund assets. The Investment Manager evaluates the appropriate form of asset allocation table and updates the S&P 500 Index trading range bands within the table at least annually. From May 1, 2020 through April 30, 2021, the form of asset allocation table in place for the Fund reflected the Investment Managers determination that the equity market was normal. With the normal form of table, the Funds equity investment allocations could be no less than 50% of Fund assets. The Investment Manager chooses the Portfolio Funds to be generally consistent with the composition of the Funds primary stock and bond benchmarks and to allow the Fund to participate in strategies the Investment Manager believes can provide additional return due to active management. The stock and bond Portfolio Funds that the Fund currently uses in its fund-of-funds structure, and the current target percentage for each Portfolio Fund within the stock or bond asset class, is set forth in the More Information Principal Investment Strategies section of the statutory prospectus for the Fund. The Investment Manager may substitute or add additional Portfolio Funds at any time, including funds introduced after the date of this prospectus. See the Appendix B: Portfolio Funds Investment Objectives and Strategies section of the Funds statutory prospectus for information about the Portfolio Funds investment objectives and principal investment strategies. Each of the Portfolio Funds is managed by the Investment Manager or its affiliates. The Fund does not pay any sales charges on its purchases of shares of the Portfolio Funds. The Investment Manager will conduct the market state review at least annually prior to the annual updating of this prospectus, and may, in its discretion, assess the market state on an emergency basis and make any changes deemed necessary to reflect, for example, a very significant move in market levels or a structural change affecting the markets. Any such emergency changes by the Investment Manager, which are expected to be infrequent, would be disclosed in this prospectus. Show less