The Vanguard Total Stock Market Index Fund, is the largest single investment fund.
With assets of £178,592 Million (£178 Billion) =[US$ 287.68 Billion]

The top ten holdings account for 14.5% of the fund = £25.89 Billion

1 Apple Inc.
2 Exxon Mobil Corp.
3 Google Inc.
4 General Electric Co.
5 Microsoft Corp.
6 Johnson & Johnson
7 Chevron Corp.
8 Wells Fargo & Co.
9 Procter & Gamble Co.
10 Berkshire Hathaway Inc.

Not entirely suprising the fund invests in some of the worlds largest companies, it is tracking the global stock market, that is of course dominated by the largest corporates in the world.

[http://finance.yahoo.com/q?s=VTSMX]

this fund overtook the famous Pimco Total Return Bond Fund, which for the past years was the largest investment fund, run by Bill Gross.
The Vanguard Total Stock Market Index Fund is run by computer, as it is an index tracker, thus Vanguard are able to offer low charges on the fund to investors, and not pay high fees for money managers.

[https://personal.vanguard.com/us/funds/snapshot?FundId=0085&FundIntExt=INT#tab=0]