The qualified investors who wish to bid for Satyam Computer Services Ltd should have total net assets in excess Rs750 crore ($150 million), the Securities and Exchange Board of India (SEBI) said ysterday while approving Satyam's bidding process.

Satyam had sought SEBI nod for a global competitive bidding for selling 51 per cent equity stake in the company.

With the clearance from SEBI, the company expects to invite expressions of interest from qualified investors shortly.

SEBI had amended the takeover regulations and eased pricing norms as the current merger and acquisition framework was not adequate to deal with an incident like Satyam, SEBI chairman CB Bhave said at a conference in Mumbai.

The regulator has imposed a few conditions. It said the investor would not be permitted to sell any acquired equity shares of Satyam for a period of three years from the date of acquisition, although the investor would be able to subscribe for additional equity shares.

''The bidding process will begin shortly,'' Satyam board member Deepak Parekh said. Parekh, along with Satyam chairman Kiran Karnik and board member Tarun Das, met corporate affairs minister P C Gupta in New Delhi on Friday.

The Company Law Board's (CLB) principal bench in New Delhi had earlier authorised the company's board of directors to select an investor, subject to certain conditions.

The minister said a retired Supreme Court judge would be overseeing the whole process.

The process is expected to include subscription by the selected investor of newly issued equity shares representing 31 per cent of the company's share capital. Thereafter, the investor will be required to make a mandatory minimum public open offer to purchase a minimum of 20 per cent of the company's capital.

''The open offer will be made at the same share price paid by the investor for the subscription,'' it said in a statement.

The reserve or floor price will be fixed by the board.

If the investor acquires less than 51 per cent of the stake through the subscription and the open offer, the investor would have the right to subscribe to additional newly issued equity shares so that the shares acquired by the investor through the three related steps (the initial subscription, open offer and the subsequent subscription, if any) will result in the investor acquiring a 51-per cent. The subsequent subscription, if any, will not result in requiring a further open offer.

SEBI's approval comes after the CLB authorised the Satyam Board to make a preferential allotment of equity shares to a strategic investor and raised the company's authorised capital to Rs280 crore from Rs160 crore, or to 140 crore shares from 80 crore shares.

Of the authorised capital of 80 crore shares, Satyam has already issued 67.3 crore shares. A strategic investor who acquires 31 per cent of the stake will have 30.31 crore shares of the company.

He will also get another 19.54 crore shares if the 20-per cent mandatory open offer is fully subscribed to by shareholders, taking the total number of shares to 49.85 crore.

Analysts expect that the investor could infuse around Rs1,212 crore of capital if the price for the preferential allotment is Rs40 per share. If shareholders fully subscribe to the 20 per cent open offer, the investor would have to pay them around Rs780 crore.

Larsen & Toubro, which controls about 12 per cent of Satyam, Tech Mahindra, Spice group, the Hindujas and some private equity firms had earlier evinced interest in acquiring the company. Market buzz is that IBM, Hewlett-Packard Co and Computer Sciences Corp are also interested in Satyam.

However, reports say that IBM, the world's largest technology services company, is unlikely to bid for Satyam as the advantage of expanding in India is outweighed by the legal and financial risks related to Satyam's accounting scandal.

Rumours of IBM's interest in Satyam have circulated for years, as the two compete on technology outsourcing and computer-related services.

Experts opine that the lack of clarity on the extent of Satyam's liabilities may hold back many prospective buyers. Satyam faces a class-action lawsuit from US shareholders that any new owner would have to assume some degree of liability.

Fraud-hit Satyam's market value has plunged to about $550 million, from $7 billion last May.

Satyam provides back office operations to more than 600 global customers, including General Electric Coand Qantas Airways.

Satyam shares fared well on the Bombay Stock Exchange on Friday following the SEBI clearance for the stake sale and closed 19.94 per cent higher at Rs42.10 from Thursday's close of Rs35.10.