Italian market watchdog Consob is looking into two contradictory statements made by BlackRock Inc , the world's largest asset manager, over its stake in UniCredit SpA , a source close to Consob told Reuters on Wednesday.

BlackRock said on Wednesday its holding in the Italian bank stood at 3.09 percent, retracting an earlier statement which said it had cut its stake to 1.71 percent just days before the launch of UniCredit's 7.5 billion euro ($9.6 billion) rights issue.

We are making checks on this, the source said. BlackRock says they made a mistake, but there is a capital increase underway, it's a systemically important financial institution and a European blue chip -- so we have to look into this, the source added.

On January 2, Consob said it had been notified by BlackRock of a stake reduction to 1.7 percent from 4 percent.

In its statement on Wednesday, BlackRock said: This change in holding was generated as a result of a corporate action, not through a reduction in holdings in UniCredit by BlackRock. BlackRock's aggregated holding in UniCredit Spa remained unchanged and as of the 28th of December 2011 ... was at 3.09 percent.

The notification therefore should not have been issued.

Blackrock said it had issued a retraction of the notification to Consob and UniCredit on January 6.

UniCredit shares have fallen sharply since it announced a steep discount on the price of its rights issue, which began on Monday and is regarded as a crucial test of investors' confidence in the European banking sector.

The first statement of a stake reduction by BlackRock was cited by media and analysts as a sign of weak appetite for the rights issue by institutional investors.

UniCredit shares -- and the rights to buy into the cash call -- rebounded on Tuesday after heavy losses on the first day of the capital increase, and extended their rise on Wednesday. The stock was up 5.9 percent at 2.5680 by 1056 GMT, while the rights gained 28.5 percent at 1.0910.

The market seems to think that the stock hit rock bottom on Monday. Yesterday, when the shares started to recover, there was a growing interest by many foreign investors, said a London-based trader.

($1 = 0.7826 euros)

(Reporting by Paola Arosio; Editing by David Holmes)