National Funding, a San Diego-based private small business lender, said it entered into a loan agreement for $50 million with CapitalSource, a division of Pacific Western Bank, based in Los Angeles and a specialist in loans to small and mid-market businesses.

The new credit line, a secured, three-year loan, provides National Funding with more flexibility to capitalize on key marketplace opportunities, the company said.

“This is a significant relationship that will allow us to increase the amount we can lend to our customers and grow National Funding in new and exciting ways,” said Dave Gilbert, CEO and founder.

National Funding mainly does working capital loans, equipment financing, merchant cash advances and credit card processing. The business’s pace of growth in recent years was sufficient to land it on both the Inc. 5000 list and the San Diego Business Journal’s List of Fastest Growing Private Companies. During the 2011-2013 timeframe, National Funding grew from $14 million to $26.5 million in revenue, ranking it No. 58 on this year’s Fastest Growing Private Companies list.