The £2.6bn (€3.1bn) West Sussex Pension Fund has begun searching for an investment manager as its £1.2bn mandate with Baillie Gifford expires later this year.

The local authority pension fund only assigned two mandates to its equities and fixed income holdings, which account for over 80% of assets.

It currently uses two traditional balanced portfolios for its £2.2bn allocations to the asset classes, split between Baillie Gifford and UBS Global Asset Management (UBS GAM), with the former’s £1.2bn mandate coming to an end in December.

“West Sussex County Council will shortly be seeking to tender a contract for the provision of investment management services for a balanced fund manager, who will be complimentary to the fund’s existing manager,” the fund said in a statement.

It is expected to be worth up to £300m in revenue for the successful manager, running for a decade and functioning as a framework agreement for local authority funds in neighbouring councils.

The fund said the two significantly sized mandates compliment one another based on investment styles at Baillie Gifford and UBS GAM, with the former using a growth style and the latter employing a value bias.

In its last full year under the current contract, Baillie Gifford outperformed its benchmark by 5.3 percentage points, providing an overall return of 10.4%.

Its mandate began in 2007 and was extended for a further four years at the end of 2010.

Overall, the fund holds close to 60% in global equities managed across the two managers, with almost 6% in UK equities.

It holds 18.7% in fixed income, predominately managed by UBS GAM, with 10% in property and 5% in private equity.

Across the two managers and its other holdings, the fund returned 10.3% over the year to April 2014, however, liabilities increased by £300m to £3.2bn, leaving it with an £800m shortfall.

Its property holdings managed by Cushman & Wakefield Investors (CWI) returned 15.1% over the year, however, in April IPE revealed the fund was ending its relationship with CWI after 22 years over performance concerns.

From April this year, Aberdeen Asset Management has managed its allocations to property.