(Adds detail on Inbursa subsidiary, AT&T stake sale)
MEXICO CITY, March 19 (Reuters) - A subsidiary of Mexican billionaire Carlos Slim's Grupo Financiero Inbursa bank has entered two loan agreements for nearly $700 million, pledging America Movil stock as collateral, according to a filing published on Thursday.
The unit, Control Empresariales de Capitales, agreed on March 11 with HSBC to borrow up to 300 million euros ($319.53 million) and pledge 544,470,143 America Movil L shares as collateral, the filing to the U.S. Securities and Exchange Commission showed.
The same unit entered a separate agreement with Caixabank in December to borrow up to 350 million euros ($372.75 million) with 596,097,178 America Movil L shares as collateral, the filing said.
The number of shares pledged to HSBC may vary going forward, according to the filing, which said that the shares must be 150 percent of the amount borrowed from HSBC.
A spokeswoman for America Movil, the telecoms company which Slim controls, did not immediately respond to a request for comment.
It was not immediately clear what use Inbursa might have for the loans. The bank, Mexico's No. 7 with 291 billion pesos ($19.04 billion) in assets, in March agreed to buy the Brazilian unit of South Africa's Standard Bank Group for $45 million.
Previous filings, which refer to Inbursa's subsidiary slightly differently as "Control Empresarial de Capitales", show that it acquired America Movil shares when AT&T last year divested its holding in Slim's flagship company.
AT&T sold the America Movil stake as part of efforts to gain regulatory approval for its purchase of DirecTV.
Separately, Thursday's filing showed that the control trust that holds America Movil shares for Slim and his family has acquired 92.1 million L shares since the family's last filing was published in January.
America Movil L shares closed down 2.18 percent at 15.73 pesos on Thursday. The shares are down 4 percent year to date. ($1 = 0.9389 euros) ($1 = 15.2800 Mexican pesos) (Reporting by Elinor Comlay; Editing by Grant McCool)