I haven't studied Saints' accounts, but I do know that over the past couple of years we have made a couple of hefty "investment" payments for other than incoming transfer fees.
One was the cost of the new training facility upgrade, reported to be nearly £40m and the other was to pay off a lingering Cortese-era BVI loan at around £30m.
In my mind I see that as the company clearing up its legacy debt using part of the "windfall" transfer fees, so freeing up more future revenue streams for squad-related expenditure. I think that's a good thing.