A filing with Dutch financial market regulator AFM shows that Morgan Stanley has the equivalent of 10.01 percent in KPN, ranking behind The Capital Group Companies.

Morgan Stanley's position was registered on May 4, the same day that KPN stock hit a seven-year low of 6.349 euros and just three days before Slim's company, America Movil (AMXL.MX), said it would offer 8 euros per share, or about 2.64 billion euros, to buy up to 28 percent of the Dutch company.

It was not clear whether Morgan Stanley, which declined to comment, held the stake on its own account or for clients.

A Dutch spokeswoman for America Movil said Morgan Stanley was not holding KPN shares on behalf of the Mexican company.

KPN said on Tuesday that the unsolicited offer undervalued its business and has hired Goldman Sachs and JP Morgan to help it weigh its "strategic options".

KPN shares were down 1.4 percent at 7.622 euros at 0813 GMT.

America Movil said on Tuesday it currently owns about 4.8 percent of KPN after buying shares in the open market. A spokeswoman declined to say which bank was holding the stake on its behalf.

Deutsche Bank is advising America Movil on the KPN deal, which would also involve handling the tender offer if it goes ahead, while Clifford Chance is advising it on legal matters.

Deutsche Bank's press office in the Netherlands was not immediately available for comment.

Capital Research and Management Company, part of The Capital Group Companies, is the biggest investor in KPN, according to Reuters data.

It lifted its interest to 15.1 percent from 10.1 percent, according to AFM filings, in January. The Capital Group Companies, based in the United States, is a group of investment management firms.

Morgan Stanley had a direct capital stake of 4.93 percent, and owned the remaining 5.08 percent in futures, options and swaps, the regulatory filing with the AFM showed.

It did not own an interest in KPN - either via shares, options, American depository receipts, or swaps - that in total amounted to 5 percent or more before the filing was made on May 4.

(Reporting by Sara Webb and Gilbert Kreijger; Editing by Will Waterman)

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