LONDON -- The FTSE 100 (INDEX: ^FTSE) didn't really move overall this week, ending at 5,652 points, as the U.K. reached the start of interim reporting season for many of the FTSE's big companies.

The index of top stocks did climb to 5,718 points on Thursday but fell back to end the week just 4 points down from last week's closing level of 5,666 points, as fresh eurozone fears took a grip again after Spanish bond yields hit a new high.

But the aggregate level of an index hides a multitude of individual companies. Let's take a look at a few of the week's big movers from among the various FTSE indices.

CSR (LSE: CSR.L)
CSR jumped 80.6 pence (37%) this week, to end at 299 pence, after the wireless communications technology specialist sold some of its operations to South Korea's Samsung. For $310 million in cash, Samsung will get CSR's handset connectivity and location technology and will invest a further $34.4 million in buying a 4.9% stake in CSR.

Second-quarter revenues at CSR are now expected to be toward the upper end of previous guidance of $245 million to $265 million.

SuperGroup (LSE: SGP.L)
Fashion retailer SuperGroup, owner of the Superdry brand, staged the next part of its recovery this week, soaring 64 pence (16%) to 450 pence.

Confidence appears to be returning after the company confessed that last year's profit warnings were all due to its own management failings (which we all knew anyway), including getting its sums wrong. Let's hope someone has bought a new calculator.

SuperGroup shares are now up 186 pence (70%) since mid-June, but they're still way down from the heady heights of 1,820 pence at the peak of last year's boom.

G4S (LSE: GFS.L)
G4S, the firm at the center of the London Olympics security debacle, slumped a further 37 pence (13%) to 242 pence, as fallout from its failure to supply the contracted levels of security staff to the games continues. The failed contract could cost G4S around 50 million pounds ($78 million).

After the U.K. government had to turn to armed forces personnel, putting an additional 3,500 troops on standby, doubts about the company's long-term prospects for public-sector contracts contributed to the selloff.

Resolution (LSE: RSL.L)
Life assurance firm Resolution crashed by 22 pence (10%) to a low of 206 pence, before recovering to end at 215 pence, after announcing a U-turn on its plan to return cash to shareholders.

The 250 million pound ($390 million) payout, equivalent to 18 pence per share, had originally been scheduled for the first half of 2012 but was cancelled after further consideration of the firm's capital requirements. "I understand that shareholders will be very disappointed," Chairman Mike Biggs said. But there could still be a 9% dividend in the cards.

What now?
As usual, this week's FTSE trading provided some large share-price movements -- and perhaps some buying opportunities. Indeed, legendary investor Warren Buffett has spent more than $1 billion buying the shares of one of the U.K.'s most successful FTSE large caps.

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Alan Oscroft owns no shares mentioned in this article. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. Try any of our Foolish newsletter services free for 30 days. The Motley Fool has a disclosure policy.