Tiphook spent pounds 1.8m on a 10 per cent stake in a company with total net assets - according to last filed records - were valued at pounds 3.9m.
The investment was part of a complex set of financial arrangements orchestrated by Tiphook in the final days of its last financial year.
The transactions are likely to be looked at carefully by Coopers & Lybrand, the accountants commissioned by Tiphook's bankers to conduct a thorough review of the company's operations and financing needs.
Tiphook, which is in the throes of refinancing talks with its bankers, invested the pounds 1.8m in the ordinary shares of Thomas Storey, a Stockport-based company that specialises in the engineering parts for Bailey bridges, a bridge system developed by Sir Donald Bailey that is sold in 60 countries throughout the world.
Tiphook also bought pounds 2.5m of preference shares in Thomas Storey, which pay an interest rate of 4 per cent.
The investment in the two classes of shares in Thomas Storey are listed in Tiphook's accounts as additions to the company's fixed asset investments of pounds 4.3m.
Together they effectively wipe out a provision relating to the write-off of pounds 4m worth of preference shares that Tiphook owned in Adamson Modular Systems, a company that went into administrative receivership in February.
Analysts have queried the pounds 1.8m investment in the ordinary shares, suggesting that this might overvalue the investment by around pounds 1.5m unless the net assets of Thomas Storey have appreciated considerably since the last set of published accounts.
A Tiphook spokesman had no comment to make on the valuation. Thomas Storey's latest report and accounts, for the year ending December 1992, have yet to be filed at Companies House.
A Tiphook source said that the valuation of the ordinary shares takes into account a number of factors, including historical and forecast net asset values, cash flows and profits of Thomas Storey.
Analysts are also querying the reason for the pounds 2.5m investment in Thomas Storey's preference shares, given Tiphook's well-publicised financial problems.
Tiphook also bought a property from Thomas Storey for pounds 5m - the latter's factory at Tiviot, near Stockport.
The last time the land and buildings were valued in the Thomas Storey accounts, in the year ending December 1990, they were given a value in excess of book value of pounds 1.03m, nearly pounds 4m less than the Tiphook purchase price.
Tiphook says that the property was written into the company's books at pounds 2.5m, on the advice of its auditors, Touche Ross.
Tiphook maintains that the site has significant development potential.
The company has been reported as being unable to give its bankers a 'comfort' letter guaranteeing that it has sufficient funds to meet its funding obligations over the next 12 months. Tiphook's shares finished the week at 95p, near an all-time low.