Barclays has declined to comment on a newspaper report that it may sweeten its 65bn-euro ($86bn; £44bn) takeover offer for Dutch banking rival ABN Amro.
ABN's board has backed Barclays' current offer
According to the Financial Times (FT), the UK bank may restructure its current all-share offer into one that includes a proportion of cash.
The FT adds that Barclays will do this if the consortium led by Royal Bank of Scotland (RBS) makes a formal bid.
However, RBS's 71.1bn-euro proposed bid depends on the future of ABN's US unit.
RBS and its partners - Banco Santander of Spain and Belgian-Dutch group Fortis - have said they will not buy ABN if US-based LaSalle is already sold off.
At present ABN shareholders have gone to court to block the Dutch bank's deal to sell LaSalle to Bank of America.
The Dutch Supreme Court is expected to rule on this by mid-July.
Barclays' current bid has the backing of ABN's board, but a number of Barclays shareholders have expressed their fears over the bank's plans to buy ABN.
US hedge fund Atticus Capital said it was concerned Barclays could get sucked into "an auction at inflated prices".