Mr Gilbert, whose 30-year-old creation has been sitting on £266m of cash, said the deals were "infill acquisitions that will assist with growing our business organically".
The shares were among the FTSE-100's biggest risers, up 8p at 424p, valuing Aberdeen at just less than £5bn, seven times its value in the depths of the split-cap crisis which almost sunk the group a decade ago.
But finance director Bill Rattray said Mr Gilbert was in no hurry to spend the rest of the cash. "We have been keen to grow the balance sheet so we are meeting regulatory requirements, and he is very clear that we will consider the odd infill acquisition as and when it comes along, rather than going out searching for targets."
The bigger deal is in the US, the acquisition for a net $45m (£29m) in cash of publicly listed Artio Global Investors, which has $14.3bn of assets under management.
That adds about 25% to Aberdeen's current US assets but will give a boost to its ambitions in the retail market, where Artio has $7bn in mutual funds and a global high yield bond product.
Artio's fixed-income business claims top quartile performance, while the £2.9bn equities business will be transferred to Aberdeen's global equity process.
Mr Gilbert said: "The integration of Artio's operations will strengthen further our US fixed income expertise, in particular the addition of US total return and global high yield products, and will help to broaden and deepen our distribution network in the US."
The smaller deal sees Aberdeen paying £17.5m to take a 50.1% stake, with the option of buying the rest in three years' time, in a private equity fund of funds business SVG Advisers. It will transform Aberdeen's £700m private equity arm with the injection of £4bn from SVGA, a subsidiary of the quoted SVG Capital, whose chief executive Lynn Fordham will lead the new business.
Mr Gilbert said: "SVGA's track record, combined with Aberdeen's own asset management expertise and global distribution network, will position us well to meet demand from investors seeking exposure to private equity. Institutional investors are increasingly looking towards alternative asset classes ... to diversify their portfolios and offer additional sources of alpha."