Jan 6 (Reuters) - British company executives became a little more optimistic following finance minister Rachel Reeves' budget and grew more willing to increase investment, although the mood overall stayed muted, a survey showed on Tuesday.

The quarterly net balance of business optimism from accountants Deloitte improved to -13% in the fourth quarter of 2025 from -24% in the third quarter, while remaining below average.

"Business sentiment is subdued but more positive than a year ago," Deloitte chief economist Ian Stewart.

Reeves announced 26 billion pounds ($35 billion) of tax hikes in November but delayed most of them and the increases were much less focused on businesses than in her first budget in 2024.

The Deloitte survey of 55 chief financial officers at major companies was conducted between December 2 and December 14.

Preliminary figures from last month's S&P Global Purchasing Managers' Index - another closely watched set of surveys - also painted a picture of tentative improvements in morale across British boardrooms.

"While CFOs remain cautious about geopolitics and productivity, business confidence and risk appetite have ticked up from their autumn lows and perceptions of external uncertainty have edged lower," Deloitte's Stewart said.

The proportion of executives who see raising capital expenditure as a strong priority rose to a two-and-a-half-year high of 17%. 

A final version of December's PMI for the services sector is due later on Tuesday. Last week, the manufacturing index pointed to a tepid upturn in late 2025 for a sector that has struggled for momentum in recent years.

(Reporting by Andy Bruce; editing by David Milliken)