Chelsea have reportedly submitted a fresh offer of £45m to Everton in order to sign long-term target John Stones.
The Blues were in hot pursuit of the 21-year-old centre-back over the summer but had every one of their bids knocked back by the Toffees, including a final offer of £30m before the transfer window closed.
Now Chelsea owner Roman Abramovich has sanctioned a 50% hike in the fee in the hope that £45m will be enough to get the deal over the line this month, according to Spanish website Fichajes.net.
Everton manager Roberto Martinez last month sent out a warning to Stones's admirers, insisting that any move in January was "not even a consideration".
Arsenal, Manchester United and Barcelona have also been credited with an interest in Stones.