In 2022, Acumen raised $60.9 million in philanthropic capital, an increase of 112.1% from 2021. Acumen recognized non-cash revenue of $2.1 million for donated legal services and donated goods to support our investing work.
We received $0.1 million in interest income from portfolio loans and recorded a loss provision of $3.9 million for portfolio investment losses. Acumen carries our program investments at cost, and we lower these valuations when impairment exists. We review our portfolio of assets on an annual basis and apply a consistent valuation philosophy across the companies in our portfolio. Because we carry these investments at cost, we do not mark up our equity investments to fair market value, even when subsequent funding rounds imply an increase in the holding value of our investments. The only exception would be mark-ups related to orderly transactions of identical shares. Any other increase in value of equity investments would be recognized as realized gains or profits upon exit.
Operating expenses represents all the direct costs related to the running of Acumen programs as well as our management and general and fundraising costs. They do not reflect any of our investments in our portfolio companies. Total expenses for 2022 were $32.7 million, a 6.5% increase compared to the prior year driven by additional headcount and research costs to support new programs.