(ShareCast News) - The FTSE 100 has failed to regain any traction on the week, with the blue chip market down 21.60 points (2.00%) to 5,966.45 by mid-afternoon Friday.Old Mutual again led the fallers, still reeling from political issues in South Africa. It's the second day of major falls for the company after a broker downgrade and weaker rand weighed on the stock on Thursday. It comes after South Africa's president unexpectedly sacked finance minister Nhlanhla Nene."Removing him (moved elsewhere is the party line) after just two and a half years and installing the unknown David van Rooyen is a decision that has sent the ZAR to all times lows and resulted in foreign investors running for the savannah, worried about the impact on an already troubled yet key mining sector," said Accendo Markets' Mike van Dulken.Anglo American dived after Goldman Sachs reiterated its 'sell' rating and slashed the target price from 430p to 280p. It commented that there are only two ways the company can get out of balance sheet pressure. "1) delivering on its strategy of increasing free cash from core assets and exiting the underperforming, cash-burning assets fast enough before increasing leverage causes financial distress or 2) seeing commodity prices improve and a significant turnaround in FCF."Glencore also sank, reversing some of yesterday's gains made after it said it had increased its planned target of reducing debt and preserving capital to the tune of $13bn (£8.6bn). It said it has already locked in $8.7bn of its target and is also planning to bring net debt down to between $18bn and $19bn, with the previous target being in the low $20bns, as well as cutting capital expenditure to $5.7bn this year and $3.8bn next year, down from $6bn and $5bn respectively. It also revealed it is examining a potential initial public offer (IPO) of the commodity group's agriculture business and has been in talks about the potential sale of some infrastructure assets.Of the very few risers, motor insurer Admiral Group drove to the top after Goldman Sachs upgraded the price target for the company from 1,500p to 1,600p. It reflected its increased earnings capacity owing to the improvement in Admiral's expected ultimate loss ratio forecasts disclosed at the point of its last financial results.FTSE 100 - RisersAdmiral Group (ADM) 1,623.00p 0.93%Merlin Entertainments (MERL) 434.90p 0.35%FTSE 100 - FallersOld Mutual (OML) 154.90p -11.08%Anglo American (AAL) 292.75p -8.13%BHP Billiton (BLT) 689.60p -5.95%Glencore (GLEN) 83.81p -5.73%Rio Tinto (RIO) 1,875.00p -4.87%Royal Dutch Shell 'B' (RDSB) 1,462.50p -4.63%BG Group (BG.) 932.00p -4.47%Tesco (TSCO) 144.00p -4.35%Royal Dutch Shell 'A' (RDSA) 1,457.00p -4.27%Antofagasta (ANTO) 427.50p -4.15%