Northern Trust said it plans to acquire technology-driven hedge fund administration firm Omnium from Citadel, the large Chicago asset manager and market-making firm.

BNY Mellon announced Thursday it has agreed to buy Chicago-based Talon Asset Management' s wealth management operations, which have more than $800 million in assets under management.

Horizon Asset Management and Kinetics Asset Management announced Thursday that they will merge on May 1 to form Horizon Kinetics, an investment advisor with $9.8 billion in assets under management.

Charles Schwab Corp. said it will acquire the online brokerage optionsXpress Holdings for $1.0 billion.

Northern Trust announced Thursday it reached an agreement to buy the fund administration, investment operations outsourcing and custody business of the Bank of Ireland Group, Bank of Ireland Securities Services.

NYSE Euronext and Deutsche Borse announced their merger Tuesday morning, creating “the world’s premier global exchange group, the world leader in derivatives trading and risk management, and the largest, most well-known venue for capital raising and equities trading,” the exchanges said.

Manulife Asset Management has acquired the assets of Optique Capital Management of Milwaukee, Wisc. Terms of the deal were not disclosed, but the companies did say that Optique has $800 million in mutual fund and separately managed account assets under management.

Hours after the stock exchanges in London, Toronto, Montreal and Milan said they would merge, the Deutsche Börse AG and NYSE Euronext Wednesday confirmed are trying to marry.

The London Stock Exchange Group and TMX Group of Toronto said Wednesday they would combine operations in “an all-share merger of equals.’’

Bank of America Merrill Lynch has reorganized its personal retirement solutions business.

In an effort to develop jumpstart its exchange-traded fund business, Russell Investments announced Wednesday it plans to buy U.S. One Inc., a registered investment advisor and ETF provider.U.S. One is the investment advisor to the One Fund, an ETF traded on the New York Stock Exchange that provides exposure to 95% of the world’s stock markets with the objective of long-term investment growth.

In an SEC filing, Grail Advisors, a provider of actively managed exchange-traded funds launched in January 2009, indicates it may be in the process of being acquired. Should that fail, it may liquidate its actively managed ETFs.

While 2010 represented a modest improvement for mergers and acquisitions, the market for initial public offerings surged back to life, as domestic IPO activity eclipsed the previous two years, according to a report from PricewaterhouseCoopers.

Global mergers rose 19% this year from last year and the top M&A adviser in 2010 was Goldman Sachs, according to data published by Thomson Reuters.

Salient Partners LP, a $16 billion Houston-based wealth manager, has agreed to buy RDG Capital LLC, a Houston boutique wealth advisory firm.

Broadridge has acquired financial services client communications firm Forefield for $19.5 million.

Northern Trust bought Waterline Partners LLC, a Los Angeles investment advisory firm serving affluent individuals and families.The price of the deal, which closed Wednesday, was not disclosed.

Capgemini has acquired IT firm Thesys Technologies Private Ltd. of India. Terms of the deal were not released.

Broadridge Financial Solutions agreed to acquire Matrix Financial Solutions, a provider of retirement products and services for investment administrators, financial advisoers, banks and wealth management professionals.

CI Financial has entered into an agreement to acquire The Hartford’s Canadian mutual fund business, Hartford Investments Canada Corp., which has C$1.75 billion in assets under management. Terms of the deal were not disclosed.