By Jamie Robertson BBC World business presenter

Microsoft's prospects are uncertain, some analysts say

Of the 144 points that the BBC's Global 30 fell last month, 138 of them were from US stocks.

Even though the Dow Jones index of leading US shares actually rose 2.1% over the same period, the country's biggest stocks have been struggling: Citigroup, up a meagre 0.68% was the only one to turn positive in April.

Even so, 63 of those negative points were down to one stock, Microsoft (down 16.3%), which fell foul of investors after it said it was going to throw another $2.5bn (�1.35bn) or more into its internet businesses.

It highlights the danger the company believes comes from its internet rivals Google and Yahoo, but it left investors wondering what kind of return it will make on those extra billions.

"The prospects are uncertain; they haven't even announced their strategy for the online business," Richard Sherlund of Goldman Sachs said.

"Whether they can compete against Google and Yahoo is uncertain and the benefits of that are likely to come over time rather than having more immediate gratification in, say, 2007 from a sharp increase in earnings momentum from new products."

Meanwhile in the background, Microsoft's appeal against the European Commission's ruling on its alleged abuse of its monopoly position continued to bother investors.

That is awaiting judgement, but in the meantime Google has unofficially made complaints to both the European Commission and the US Justice Department about the next version of Internet Explorer, saying it unfairly funnels users to Microsoft's MSN search engine.

Unfit banker

The world's largest retail chain Walmart (down 8.0%) has run into flak over its plans to start limited banking operations to run a credit card payments clearing system, although it says it does not want to open bank branches across states.

BBC Global 30, last 12 months

Faced with some 2,900 letters of protest, the banking regulator took the unusual step of holding hearings into the application.

Opposition groups argue that the company's "low character" and past regulatory violations make it unfit to run a bank.

More evidence that shareholders are getting annoyed by the size of senior executives' pay packages: Hank McKinnell, chairman and chief executive of Pfizer (down 3.6% on the month), faced a hostile barrage from shareholders at his annual general meeting.

Daniel Pedrotty, of the AFL-CIO Investment Office that runs pension funds for US workers unions, said "the average pay for a S&P 500 chief executive is $11.75m, and increasingly that pay is being divorced from performance - in fact it is payment for failure".

"Hank McKinnell has an $83m guaranteed pension he can just walk away with on retirement, yet Pfizer's share price during his tenure has fallen 50%."

Mobile phone movers

On the plus side of the index, the oil and commodity players made less headway than you would have thought with oil topping $75 a barrel and copper and a raft of other metals hitting new peaks: Exxon was down 1.2%, BP fell 0.6% and BHP Billiton rose just 2.4%.

German utility E.On gained after landing deals in Russia

Instead the biggest gainer was Vodafone recovering from its falls in February, rising 6.6%.

Nokia had some positive forecasts for mobile phone sales - although its shares still fell 3.5% - and there was increased speculation that Verizon (down 8.3%) is keen to buy out Vodafone's 45% stake in Verizon Wireless.

On top of all that there was a report, strongly denied, in London's Daily Mail that Verizon, Telefonica and the Blackstone Group might consider a bid for the whole of Vodafone.

E.On (up 5.2%) and BASF (up 3.7%) both benefited taking a trip to Tomsk in Russia with Chancellor Merkle to sign a deal with Gazprom over the exploitation of the Yuzhno-Russkoye gas field.

BASF got a bigger than expected slice of the pie, about 35%, rather than the 25% originally thought.

Siemens shares (down 4.7%) also had a run up during the month, but then fell back after its results disappointed the market.

Chief executive Klaus Kleinfeld said growth would slow as the year progressed, despite the 16% rise in profits in the first quarter.

It also said it would buy for $1.8bn Diagnostic Products of the US and would axe 1200 jobs in the communication unit adding to speculation that it would soon be selling it off.

GlaxoSmithKline (up 2.2%) had a good set of results which accounted for gains in its shares in the last few days of the month, reflecting rising sales of vaccines and treatments for flu and childhood diseases.

The markets also welcomed its announcement that it expected to receive results of clinical trials of its H5N1, or bird flu vaccine around June this year, while ramping production of antiviral oral spray Relenza, which can have a modifying effect on influenza.

In Asia, Hutchison Whampoa rose 1.5% on the back of its deal to sell 20% of its ports business to the government owned PSA.

The deal is good for both parties: Li Ka-Shing, the controller of Hutchison gets cash to pour into his as yet unprofitable global third generation mobile phone businesses; PSA gets international exposure to an industry that's booming on the back of surging trade.

Samsung failed to shine this last month, falling 2.0%, despite increasing net income by 26%, thanks to higher sales of TV screens, even as the prices for its computer chips and mobile phones continued to fall.

Investors have been worried by its rival Hynix losing a legal patent case to Rambus of the US, and being forced to pay $307m.

Rambus has a similar case out against Samsung.

It centres round DRAM (dynamic random access memory) chips, which have become a global industry worth around $26bn a year.

Toyota, which has given shareholders around 100% growth in the last year, announced 7.4% sales growth in the US, and that by 2008 it would introduce ethanol fuel cars into the US market.