CRA does not require 3rd party commitment letters for loss transfer rulings

When asked whether, in a loss consolidation transaction, it matters whether the lossco has a source of funds to cover dividend payments other than the interest income paid by the profitco, CRA responded that in upstream shareholding situations, it will "generally ask for a representation that the issuer of the shares will have other assets from which the dividends will be funded" – and when asked whether it requires a commitment letter issued by a third party to confirm that the proposed transactions are commercially plausible, it responded:

[T]ypically the CRA will request a representation relating to borrowing capacity. In some cases, such as situations where the amount of the debt is substantial, CRA may request a signed letter from a director or other documentation.

Neal Armstrong. Summary of 19 August 2015 T.I. 2015-0589611E5 under s. 111(1)(a).