Marsh & McLennan Cos. Inc. reported a second-quarter net loss this morning, partly due to a write-down of the value of its security consulting business. The net loss of $193 million, or 37 cents a share, compared with a year-earlier profit of $65 million, or 12 cents a share. Excluding one-time items, the company posted a profit that matched the average Wall Street forecast.

The world’s second-largest insurance broker, Marsh employs an estimated 1,200 people at its Urbandale location. .

Marsh said it wrote down the value of its Kroll security consulting business, resulting in a non-cash charge of $315 million, or about 60 cents a share. It also recorded a loss of $31 million due to the declining value of its private-equity investments. The New York-based broker, which competes with Aon Corp. in helping businesses find commercial insurance coverage, said consolidated revenues fell 13 percent to $2.6 billion, less than the average estimate of $2.76 billion.

Revenues within its main business unit, insurance brokerage Marsh Inc., fell 7 percent to $1.1 billion on lower insurance premiums.

Insurance rates have been falling in recent years, costing brokers who are largely compensated by commissions. In response, most brokers have curbed spending. Marsh & McLennan’s expenses in the quarter were down 7 percent from a year earlier to $2.65 billion, boosting the underlying profitability of some of its businesses.

The company’s shares rose nearly 3 percent on Tuesday to $21.50. The stock has traded in a range of $17.23 to $35 in the last year.