Half-year results from the Co-operative Group and its stricken banking arm will take centre stage this week, while under-pressure support services firms G4S and Serco are also due to report.

More details of the Co-operative Bank’s woes will be unveiled on Thursday when it posts its first set of figures since being thrown into turmoil after revealing a mammoth hole in its finances.

Parent company the Co-operative Group will attempt to convince investors that a punishing £1.5billion fundraising is the only way to plug its balance sheet shortfall.

The rescue needs the backing of investors through a “bail-in” andbBondholders ranging from pensioners to US vulture funds must accept losses on their investments if the deal is to progress.

The bail-in will raise £500m of capital by offering bondholders shares via an “exchange offer”, resulting in a stock market listing for the group’s banking arm.

But the turnaround has been complicated by US hedge funds seizing control of some of the bank’s loans, giving them a strong bargaining position in the bail-in talks and potentially forcing even higher losses on lower-ranked retail bond investors.

The Co-op is also sharing the pain by selling its insurance businesses and raising new debt but it must also bolster its finances by slashing costs, with some of this expected to come from job losses among the bank’s 10,000 staff.

Support services groups G4S and Serco will reveal the impact of high-profile rows with the Government when they publish first-half results.

The fallout from G4S’s 2012 Olympics staffing failure was compounded when a new scandal emerged earlier this year around overcharging for electronically tagging offenders.

Auditors found both G4S and Serco overcharged the Government by “tens of millions of pounds” by billing for tagging offenders who were back in prison, had their tags removed, had left the country, had never been tagged in the first place or had died.

Serco faces a forensic audit while G4S has been referred to the Serious Fraud Office.

G4S, which reports on Wednesday, is forecast by Cantor Fitzgerald to see underlying annual profits dip to £408.7m this year, from £412m a year earlier.

However, Investec expects Serco, which reports its interims in Thursday, to post underlying full-year profits of £283.2m, up 4% on £271.6m in 2012, as previous contract wins filter through.

Recruitment firm Hays announces full-year results on Thursday after a turnaround in the performance of its embattled UK division in the last quarter, but the improvement is not expected to be enough to have saved the group from an overall fall in profits.

UK and Ireland net fees were up 7% in the three months to the end of June, bolstered by a 12% increase for temporary jobs, although recruitment for permanent roles was flat.

The group said at the time of the update that full-year operating profits were expected to be at the top end of analysts expectations of £112.3m to £125.5m, but this would still be below the £128.1m seen the previous year. Analysts at Numis predict pre-tax profits of £119m, a fall of 2.8%.

Paving slabs specialist Marshalls reports half-year figures on Friday after sliding sales during a period hit by freezing weather.

The company revealed last month that revenues for the six months to the end of June were down 4% at £163m after trading suffered amid the coldest March in more than 100 years.

But it said customer sentiment and orders increased in May and June, adding to hopes for an upturn in prospects, while cost reduction measures instigated last year were delivering positive results.

Analysts are optimistic about the future, with a forecast for full-year pre-tax profits of £12.7m.