Middlesbrough brought in no less than 12 new players including the likes of midfielder Martin Payero, full-back Lee Peltier and goalkeeper Luke Daniels all signings permanent deals to see them arrive at the Riverside Stadium.
One area of real interest in modern football is how well clubs invest talent to sell on, with the wildly inflated market meaning a player could be bought for a bargain fee one season and flogged for big money the next.
At the opposite end of the spectrum, some players command multi-million pound fees, before winding down their contracts and leaving for nothing a few years later.
Now the window has closed, we've taken a look (via BettingOdds.com) at how much profit on previously purchased players every Championship club has made over the last five years. Sales of academy players are also factored into the figures.
This is how Middlesbrough's profit percentage on players sold ranks alongside all of their divisional rivals over the past half-decade of transfer activity: