The sixth successive daily drop in oil prices — the longest losing streak for crude this year - made it a bad day for Tullow Oil to issue its half-year trading statement.

But while shares in the £7 billion oil and gas explorer retreated 3 per cent, there were other factors at work. First, its update might be considered mildly disappointing. The drilling of its eagerly awaited Ngassa-2 well in Uganda's Lake Albert rift basin has been slower than anticipated, meaning that the results — expected within days — have been delayed for at least a month.

Further, lower oil prices combined with reduced production — it is forecasting 58,000 barrels of oil equivalent per day this year, against 60,000 previously — mean that first-half revenues will be down 23 per cent on 2008.

Second, Tullow's shares were pressured by speculation that, only months after tapping shareholders for £402 million, a much larger equity fundraising could be on the cards. Investors will not find any mention of it in yesterday's statement, but Kosmos Energy, Tullow's partner in Ghana — its biggest territory alongside Uganda — is up for sale, with first-round bids due next Friday.

Kosmos, which is backed by Warburg Pincus and Blackstone, has a 30 per cent stake in Ghana's Jubilee field, while Tullow has pre-emption rights over its holding. However, with Kosmos thought to be valued at between $3 billion and $4 billion (£1.8 billion and £2.5 billion), that stake would cost $1 billion, suggesting that Tullow could not fund a deal through debt alone.

The likes of BP, Royal Dutch Shell and CNOOC, of China, have expressed interest. Even if Tullow were not to participate, the auction will provide the first concrete valuation of one of its African blockbuster assets: Jubilee is estimated to contain up to 1.8billion barrels.

But the rest of yesterday's update did little to alarm. After approval from the Ghanaian Government, Tullow confirmed that it is on track to produce oil from the first phase of Jubilee in the first half of next year. Meanwhile, it is using the same techniques that produced such huge exploration success in Ghana and Uganda to push into other corners of Africa — notably Ivory Coast, Liberia and French Guinea.

But the question, as ever, remains one of valuation. Its shares — which look expensive on conventional measures and provide minimal yield — have already doubled from their November low and, up by one third this year, are already the best-performing oil stock in the FTSE 100. The longer-term issue of how Tullow will commercialise its Ugandan discoveries remains. Yet, at 863p, a busy drilling programme in West Africa in the second half of this year and the prospect of steadily rising production revenues after this year's blip give reasons to hold on.

Carillion

The Middle East may account for only one tenth of Carillion’s sales, but poor sentiment on the Gulf — or rather the overstretched emirate of Dubai — has weighed heavily on its shares. So there was some relief when the FTSE 250 construction services group confirmed yesterday that cash from its operations in the region was flowing back to the UK much as before. Of the £600 million of revenues it expects to make in the Middle East this year, £250 million has already been received. Although Carillion expects Dubai to produce only £80 million of sales this year, against £250 million last, and remain weak for the foreseeable future, Abu Dhabi has taken up the slack.

The other comfort is that Carillion’s debt is falling faster than expected. It has booked £76 million from the sale and outsourcing of its IT activities and £14 million from two PFI schools projects, but, even so, the reduction in its borrowings to £150 million denotes a tightened focus on cash.

The outlook for Carillion’s low-margin British construction activities remains a concern, particularly given the increased competition from rival builders that face falling order books. However, it is beginning to see the first benefits of British stimulus spending in its roads business — it is involved in traffic management schemes on the West Midlands motorway network — while the pipeline of potential business in the company’s support services division (it carries out property maintenance for BT, HSBC and Norwich Union) is at an all-high. Cost savings from its purchase of Alfred McAlpine give further support.

After forecast double-digit profit growth in 2009, next year’s earnings should slow — while the prospect of a general election, causing a likely hiatus in public sector decision-making, is set to provide a further drag. But at 252p, or less than seven times earnings, and yielding 5.4 per cent, those concerns are already priced in. Hold.

Telecom Plus

Forget what its name might suggest: Telecom Plus is largely a play on energy prices. That much is evident from the share price of the utilities reseller, the doubling of which in the first eight months of last year coincided with a rise in gas and electricity prices to record highs.

Sharply rising bills push more domestic customers its way: Telecom Plus uses its bulk-buying power with suppliers to secure favourable rates. Higher energy prices also spell higher margins for the middleman.

But the company is prospering even in times of cheaper oil and gas. Recession and the search for alternative sources of income have helped it to accelerate the rate of recruitment of its distributors, up 10 per cent over the past three months to 30,000. That is important, given that their number is a reliable indicator of future sales. However, at 284½p, or 16 times earnings, and the shares trading ex-dividend tomorrow, there will be better times to buy.

Explore Markets

• United States

• Europe

• Japan

• China

• Russia

• The Gulf

• India

• Africa

Times Recommends

• Lies and cover-up at MG Rover exposed by report
• High oil prices push manufacturing costs up
• Primark founder steps down as chief executive