NEW YORK (Reuters) - Internet companies are bracing for a possible decline in one of their biggest sources of advertising following the turmoil in the subprime mortgage market, the Financial Times reported.

Many online companies rely for a disproportionate amount of their income on financial services advertising, with subprime in some cases accounting for a large part of it, the FT said.

Sixteen percent of all online advertising comes from financial services companies, making it the second biggest source of advertising behind the retailing sector, the report said, citing Sandeep Aggarwal, an internet analyst at Oppenheimer.

Mortgage lenders Countrywide Financial Corp and Low Rate Source were two of the 10 biggest online advertisers in the United States in July, according to data from Nielsen/NetRatings, the report said.

(Reporting by Lewis Krauskopf)
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