Westpac will retain a 60 per cent stake in BT Investment Management once the bank lists the investment management arm of BT on the Australian Stock Exchange in December.The prospectus for the proposed float of BTIM, published late yesterday, shows the bank plans to market 32.7 per cent of shares to existing Westpac shareholders and also institutional investors, while "eligible employees" will own 7.3 per cent of shares, paid for with their labour rather than in cash.Giving the staff - and in particular management, investment strategists and investment analysts - an equity stake in BTIM is the stated rationale for the listing.The market capitalisation represents a multiple of between 16.8 times and 19.3 times the forecast net profit of BTIM for 2008 of $45.7 million. That profit forecast is the "cash" forecast for the profit according to the prospectus. The reported net profit for 2008 is expected to be $22 million lower than the cash profit since BTIM will have to amortise the cost of the free shares, if that's a fair term, allocated to staff and management.Westpac said the profit of BTIM represented about 10 per cent of the profit of BT Financial and about one per cent of the profit of the bank. Westpac will still report more than half the BTIM profit in its consolidated accounts.Investors in BTIM may not be able to count on revenue streams from Wesptac for long. The former has a contract with the latter to manage $27 billion of funds for BT for only three years, which Westpac can extend for another two at its option and also terminate for a long list of reasons including poor performance.