As noted upthread, mutual funds may buy & sell daily. Index mutual funds track a specific index, like the S&P500 or TSX Composite, so they tend to have low portfolio turnover. Actively managed funds choose holdings to try to get good performance, but do not track any specific index. Active funds may have low to very high portfolio turnover depending on the manager and the fund mandate.
One potential issue with actively managed mutual funds is they have a vague investment mandate that allows a broad range of holdings and tactics, so the fund may change over time with no requirement to notify investors unless it is a very significant change. If you don`t want the fund manager to have that leeway, consider index mutual funds or ETFs instead.
Mutual funds are required to publish their holdings. I`m not totally sure but I think they must disclose the top 25 holdings every quarter.
You can find the holdings on the fund websites. Look for a document called Fund Facts or for more detail look for the Management Report of Fund Performance (MRFP) which is published on an annual and semi-annual basis. For example the Mawer and Steadyhand fund documents can be seen at these links:
Mawer Mutual Fund Documents - Mawer
Forms and Documents - Steadyhand Investment Funds
Finiki is a great Canadian investing resource:
finiki, the Canadian financial wiki
Getting started - finiki, the Canadian financial wiki
Oh yeah... the mutual fund prospectus does not list holdings.
Edit: I just noticed I replied to a thread from 2009. 😕