The Edinburgh-based fund manager repeated the promise that it will be a "growing business" and said integration of the Ignis operations would take up to 18 months, but confirmed that its Glasgow office was likely to close in due course.
SLI said: "At this point there is no planned closure of either the Glasgow or the London office of Ignis, however in the longer term our UK estate strategy will be predominantly focused on Edinburgh and London."
Ignis employs just under 400, split evenly between fund management, operations and support, of whom 250 are in Glasgow.
SLI said that so far eight people had left Ignis "following discussions about the future structure of the business and available roles".
Its statement went on: "The vast majority of Ignis people remain in post on July 1 and there will be no immediate changes to the products and services provided by Ignis. We have identified cost savings in excess of £50m by the third full year of ownership. It is inevitable that in a transaction of this nature job losses will form a part of that, but we will be doing all we can to mitigate their impact on individuals."
Keith Skeoch, SLI's £4m-a-year chief executive, said when the deal was unveiled three months ago that there would probably be up to 200 vacancies over the next two years and he was hopeful some could be filled by "pockets of high-performing talent" at Ignis.
An SLI spokeswoman said: "We would emphasise that Standard Life Investments is a growing business. We have created nearly 300 jobs in the last five years and are confident we will create more in future and currently have 130 vacancies.
"We will speak first to our people and potential colleagues in advance of anything further being disclosed but our focus is on continuing to grow our business and redeploying talent wherever we can."
Mr Skeoch said in March he saw "real signs of strategic opportunity with this deal as well as financial benefits that come through in the short run". He said adding Ignis's £59 billion of assets to SLI's £184bn would not only create a stronger player but one with a dominant position in running insurance funds.
Ignis runs £44bn of closed funds for its parent Phoenix, which includes the Scottish Mutual, Scottish Provident and Alba Life funds.
SLI and Phoenix have agreed a "long-term strategic alliance" to secure the funds and enable SLI to benefit from future Phoenix fund acquisitions.
As to the non-insurance assets, Ignis's big Glasgow success stories have been its liquidity team which runs the Absolute Return Government Bond, and the property team which boasts the £920m UK Commercial Property Trust, the biggest in the sector.
SLI has cited Ignis's strengths as government bonds, liability management, emerging market debt, credit and real estate. On how soon jobs would start to go, a spokeswoman said: "It is too early to say; it is up to individual teams in areas of the business to sort this out. We don't want to make snap decisions, we are not that sort of business."
She said the integration was planned to be completed over an 18-month period.
Shares in Standard Life closed up 4.3p, or 1.15 per cent, at 378.4p.