MADRID, Jan 18 (Reuters) - Spain's High Court has dropped an investigation into allegations that Russian tycoon Mikhail Fridman acted to depress the share price of DIA while trying to take over the supermarket chain, two judicial sources told Reuters on Monday.

Following a drawn-out takeover bid, Fridman's LetterOne fund took control of the loss-making retailer in 2019 and rescued it from the brink of insolvency after DIA's market value fell by 90% in 2018 as it lost out to rising competition.

The High Court had been investigating since October 2019 whether Fridman may have acted to manipulate prices, engaged in insider trading and damaged the interests of minority shareholders.

But after requesting information from the CNMV market watchdog and financial crime police unit UDEF, the court agreed to drop the inquiry as investigators could not prove the accusations, one of the sources said.

The prosecutor also asked to close the case, the other source added. Both sources asked not to be named.

LetterOne declined to comment. (Reporting by Emma Pinedo; editing by Andrei Khalip and Barbara Lewis)