The slow days of summer aren't affecting hiring for Jefferies & Co., which has been beefing up staff in various businesses over the past few weeks in the U.S. and overseas.

There are no signs of a hiring slowdown in the near future at the New York-based middle-market investment bank, either. It is looking to increase staff soon in its Hong Kong office's fixed-income sales and trading group, said a person familiar with Jefferies' hiring plans. The firm also wants to build more of a presence in its financial institutions group globally, the person said.

Jefferies, similar to other middle-market investment banks and boutiques, has been hiring staff and expanding areas of business over the past year. The bank is the principal operating subsidiary of Jefferies Group Inc. (JEF).

The latest addition to Jefferies is Jon Pliner, who joined the bank as head of European credit sales and trading from Merrill Lynch this week. Pliner will be based in London.

Additionally, this month the firm added Eric Ollom in New York as chief strategist for Jefferies' emerging-markets sales and trading business within the fixed-income division. He joined from ING Groep NV (ING), where he worked for eight years. Robert Minkoff joined as a senior trader of trade claims from a distressed-debt hedge fund, Liquidity Solutions Inc. He will be responsible for building a trade claims team at Jefferies, and is based in Stamford, Conn.

Jefferies poached a few professionals from Citigroup Inc. (C) including Stephen Grahling, who will be head of event driven in the firm's equity sales and trading division, Michael Dorsey as a senior trader and Ted Chen as a senior analyst.

These hires, combined with Jefferies' existing special situations team, created a new event-driven desk within Jefferies' equity division.

Also, Jefferies made eight hires in its London and Tokyo offices within the mortgage and asset-backed securities group.

In July, Jefferies made several hires as well, among them a high-profile professional, Lisa Pendergast, to head its commercial mortgage-backed securities strategy and risk group. She joined from RBS Greenwich Capital, where she helped build and led its CMBS research operation.

Shares of Jefferies Group were trading up 1.38% at $22.05 midday Thursday.

-By Jessica Papini, Dow Jones Newswires; 212-416-2172; jessica.papini@dowjones.com