Chelsea and Manchester United would have to part with a world record fee for a full-back if they hope to prise Luke Shaw away from Southampton either this month or in the summer transfer window.
According to the Daily Star, Saints will demand £30 million for the England under-21 international - a figure that would surpass the current record paid for a full-back, held by Barcelona defender Dani Alves.
Barcelona spent £29.5 million to sign Alves from Sevilla in 2008 and, aged only 18, Shaw would also become one of the most expensive teenagers in history were Chelsea or Manchester United to complete a deal for his signature.
Chelsea are already reported to have failed in an approach of bring Shaw to Stamford Bridge but may yet make a renewed approach as Jose Mourinho sees the youngster as a long-term successor to Ashley Cole.
Manchester United, meanwhile, are known to be in the market for another left-back and, with Leighton Baines seemingly set to commit his future to Everton, Shaw could be the player David Moyes chooses to pursue.
Moyes has been keen to recruit a replacement for Patrice Evra since took the job at Old Trafford, and the France international is now expected to leave the club at the end of the season.