FACTBOX: Firms exposed to Madoff's alleged fraud

(Reuters) - Investors around the world have scrambled since Friday to assess potential losses from an alleged $50 billion fraud by Bernard Madoff, the prominent Wall Street trader arrested last week.

Following are some of the firms exposed.

* HSBC HOLDINGS PLC has potential exposure of about $1.5 billion, the Financial Times reported, citing unnamed people close to the situation. The exposure is from loans it provided to institutional clients, mainly hedge funds of funds, that wanted to invest with Madoff, the FT reported.

* GRUPO SANTANDER SA - Spain's largest bank said its investment fund Optimal has a 2.33 billion euro ($3.05 billion) exposure to Madoff Securities.

* MAN GROUP PLC - Said it is exposed through RMF, its institutional fund of funds business, which has approximately $360 million invested in two funds that are directly or indirectly sub-advised by Madoff Securities.

* BBVA - Spain's second-largest bank said its international operation has about 30 million euros exposure to Madoff, and it sees a maximum potential loss from Madoff-linked investments of 300 million euros ($404 million).

* ASCOT PARTNERS LLC - According to a Wall Street Journal report, the fund where former GMAC chairman Jacob Ezra Merkin is a money manager has an exposure of $1.8 billion.

* ACCESS INTERNATIONAL ADVISORS - According to a report by Bloomberg, Access has an exposure of $1.4 billion.

* AXA SA - Said it has negligible exposure to Madoff, well below 100 million euros.

* BARCLAYS - Any exposure for British bank Barclays Plc to Madoff would be "minimal," a person familiar with the matter said, but Barclays declined to comment.

* UNION BANCAIRE PRIVEE - Swiss bank that invests in funds of hedge funds has lost about 1 billion francs ($850 million), according to Le Temps, citing unnamed banking sources.

* ROYAL BANK OF SCOTLAND GROUP PLC - said it had exposure through trading and collateralized lending to funds of hedge funds invested with Madoff, with a potential loss of around 400 million pounds ($597.9 million)

* NATIXIS said it could have a 450 million euro ($602 million) indirect exposure to Madoff

* BNP PARIBAS - France's largest listed bank said it has a potential 350 million euro ($464.3 million) exposure.

* REICHMUTH & CO - Swiss private bank said its fund of funds Reichmuth Matterhorn had an exposure to investments linked to Madoff that amounted to about $325 million.

* NOMURA HOLDINGS said it had a 27.5 billion yen ($303 million) exposure related to Madoff, but the impact on its capital would be limited.