This blog post is sparked from a comment by Suresh Nair on yesterday's post. In it he says "The real problem comes when top management asks for ROI".
For me, this is not a problem, it is an opportunity.
Here are the four things that make this question into an opportunity.
1) Top Management are talking to you. You have access to them, and they are listening to you. A conversation with senior management has opened up. As a KM salesman, make the most of this (see "selling KM on emotion").
2) You have the opportunity to show them some success stories which demonstrate a very high ROI. KM can deliver fantastic ROI - our October 2012 Newsletter (available here) gives many examples of KM ROI, and how it can be measured, and this blog has published an occasional series of quantified success stories, with 53 examples to date. There is plenty of evidence you can show them.
3) You have the opportunity to make a deal with them. See here for how this deal might go. You promise them ROI, in return for their endorsement, example, steer, recognition and challenge.
4) You have the opportunity to offer to use KM to solve some of their real problems. Don't forget, KM works extremely well when applied at senior level - its not just for the frontline staff. Senior managers are knowledge workers too. If you can do this, they will be on your side forever (see "taking the thorn from the lions paw").
So look on this request as an opportunity to engage, and broker a deal, at the highest level. Remember John's story; seize the opportunity and be bold - it could be the best thing that happens to you.