 Shell PLC LSE:SHEL, NYSE:SHEL will later this week spend up more of its excess cash to buy back more of its own equity, thats according to analysts at Jefferies. In order for Shell to meet its shareholder returns target, to pay out over 30 of cash flow from operations, it will need to increase its share buy-back programme by US1-2bn, at the same time the US investment banks analysts reckon dividends could increase. 