(Adds Bank of Spain Governor comment, background, detail)
SANTANDER, Spain, June 20 (Reuters) - Some institutional depositors took money out of Spain's Banco Popular after its credit rating was downgraded, Economy Minister Luis de Guindos said on Tuesday, responding to a call for an investigation into deposit flight from the bank.
Banco Popular was taken over by Spain's biggest bank Banco Santander early in June when European authorities stepped in to prevent its collapse.
"The policy of institutions on where to deposit cash depends on the credit rating of the bank and that means that some institutional depositors withdrew their cash as a consequence of rating downgrades," he said.
Retail investors had also withdrawn money from the bank days before Santander agreed to buy Popular for the symbolic price of one euro, de Guindos said at a conference in the northern Spanish coastal city of Santander.
On Monday, European Central Bank supervisor Daniele Nouy was questioned in the European Parliament's economic affairs committee over a withdrawal of deposits from Popular by local and regional authorities.
"There is certainly room for the Spanish justice to investigate these movements to see whether insider information has helped certain people to try to protect themselves better," Nouy said.
Guindos said he did not know whether deposit withdrawals were due to account holders having privileged information on the bank's takeover by Santander.
Separately, Bank of Spain Governor Luis Maria Linde reiterated on Tuesday that the bank's rescue had been due to a lack of liquidity and not a solvency problem.
"The attack, the run, the flight of deposits which was seen in Popular was not due to depositors suddenly saying 'oh, there's a solvency problem, I'm leaving,'" Linde said during a hearing in parliament on the Spanish economy. (Reporting By Jesus Aguado in Santander and Sarah White in Madrid; Writing by Paul Day. Editing by Jane Merriman)