Once upon a time, we used to think that the function of the financial system was to channel savings from households - who were savings or for a rainy day - towards companies who could invest them productively*. That world has gone, and it won't return for some time if you believe the OBR's forecasts.

These show that whereas companies are expected to run a financial surplus throughout the next five years - albeit at a declining rate - households are expected to start to run a deficit.

If the OBR is right, this means that, by the end of this decade, we'll have seen 18 years in which (except for one quarter) companies have run a higher financial balance than households.

This stands on its head the old-fashioned image of financial intermediation. This now consists of transferring corporate savings to households, to spend on housing.

Now, of course the OBR's forecasts might well be wrong; forecasts are. But they seem plausible. If we see a normal upturn the share of profits in GDP will rise, as mass unemployment continues to hold wages down. Allied to a continued (if slightly lesser) dearth of investment opportunities, this will keep retained profits higher than capital spending. Meanwhile, households could respond to that squeeze on wages by saving less.

This picture is consistent with the corporate sector having gone ex-growth. It's common for large mature companies such as Next to generate more cash than they can usefully invest. "UK plc" generally has been in this position for several years, and the OBR expects it to remain so.

Curiously - as with the productivity collapse - George Osborne failed to mention this in his speech yesterday.

But it surely is of immense significance; can an economy really prosper for long merely by building and selling houses? There are two big questions here: is there anything that could usefully be done to expand investment opportunities, or to get firms to better use the few that do exist? And/or: should we think more about the policies we need in an economy that's gone ex-growth?

I'm not sure of the answers here. But as I've said before, I wouldn't mind if our political class at least bothered to ask them.

* Yes, I know banks create money. I'm talking here about shifts of real resources.