European Central Bank loans to Spain's battered banks shot up 17.2 percent to a record 337.2 billion euros ($411 billion) in June, the Bank of Spain said Friday.
Spanish banks' debts to the eurozone's banker have racked up record highs each month of this year as the banks struggle to raise money on wary interbank and debt markets.
Borrowings from the ECB, which were up from the previous month's record of 287.8 billion euros, have risen remarkably from a low point in April 2011 of 42.2 billion euros.
In two landmark but highly disputed operations in December and February, the ECB offered 1.1 trillion euros at ultra-low rates to banks.
The ECB's aim was to avert a looming credit crunch, hoping banks would lend the cheap funds to businesses and households and keep credit flowing in the debt-wracked eurozone economy.
However, ECB data suggested the banks were instead taking the money from the ECB and giving it straight back to the ultra-safe institution, fearful of lending it to riskier borrowers like other banks.
Spanish banks tapped the cheap ECB loans heavily as they sought in vain to borrow from other eurozone lenders.
Few investors are prepared to lend to Spanish banks, now paying the price of heavily over-extending themselves during a property bubble that imploded in 2008.
Spain's eurozone partners have agreed to extend a rescue loan of up to 100 billion euros to salvage the financial sector, with conditions that will include reckoning with the plunging value of banks' property assets.
On the debt market, investors demanded yields of more than 6.7 percent for Spanish 10-year government bonds in late morning trade, a level Madrid has admitted is unsustainable over the long term.
Last month, the ECB said it would widen the range of securities it accepts from eurozone banks in exchange for its loans in a move to boost lending to firms and households.
In a move that helped Spanish banks in particular, the ECB said June 22 that it would accept residential mortgage-backed securities as collateral for loans.