Tenon shares plunged 9% on its half-year results to 5.76p, putting a market value of £58 million on the UK's seventh-largest and only quoted accountant.
Lloyds was granted a warrant over 9.99% of the shares after it granted Tenon new facilities of £93m last October, an increase from £88m, as the group reported a £10m full-year increase in debt to £78m. Debt has now risen to £80.4m.
Tenon said it had made "huge progress", with the underlying operating loss cut from £10.9m a year ago to £600,000 and the pre-tax loss from £83m to £7.5m.
But the group said its cost and headcount reductions had impacted on revenues, down by £9.8m at £88.4m, and therefore its "tightly drawn" banking arrangements. It said: "The covenants and other terms of the facility tighten over time, particularly in the second half of the 2014 financial year, and were set on the basis of a larger business than we have now."
It said the group had entered into discussions with Lloyds to avert the significant risk of a facility breach over the next 12 months.
"While to date Lloyds has not agreed to this reset, we remain in positive dialogue with the bank and Lloyds has confirmed that it continues to be supportive of the continuation of the group as a going concern."
The half-year accounts also show a £14.9m provision for professional indemnity costs, including £11m for live cases, suggesting that RSM Tenon anticipates an upsurge in client claims against the company.
The group said £5.8m of its revenue slide was due to market conditions in audit, tax and advisory, lower new business wins for financial management against the background of the new fee-charging regime, and continued downward pressure on revenues in the insolvency and restructuring market.
The Herald reported on Monday how RSM Tenon had invited clients of its closed-down tax avoidance business, Premier Strategies, to consider settling potential tax liabilities.