UPDATE 1-Colombia regulator takes control of Interbolsa

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BOGOTA, Nov 2 (Reuters) - Colombia's regulator said on Friday that it was taking administrative control of the country's biggest stock brokerage, Interbolsa, over a liquidity problem.

The firm, which executes a third of the daily operations on the stock exchange, said on Thursday that it had a ``temporary liquidity constraint'' but continued to operate normally, which caused its shares to plunge 30 percent.

The regulator said on Friday that it would decide within two months, with a possible extension of another couple of months, if the brokerage could be subject to liquidation.

Clients' resources were not at risk, it said.

Colombia's stock market opens at 0830 local time (1330 GMT).

Interbolsa forms part of a group with the same name that includes insurance and investment arms and also operates in Brazil, Panama and the United States.

The move only affects the stock brokerage and not the rest of the group, the regulator said.

(Reporting by Bogota Newsroom; Editing by Gerald E. McCormick)