NEW YORK — Shares of Wella continued to jump this week, especially Thursday, when word circulated that Procter & Gamble made an offer to buy the German hair care and cosmetics firm for approximately $86 a share, nearly 23 percent more than its current share price. Speculation bolstered Wella shares as much as 17 percent during intraday trading, but the stock settled at $70.10, up $.06 a share, a 10.2 percent increase. All dollar figures are calculated from the euro at current exchange rates. As reported in these pages on Wednesday, Wella’s majority shareholders, the Ströher family, are reconsidering the sale of the company. Other reported bidders include Unilever and L’Oréal. Last October, Wella reportedly turned down an informal $5.7 billion from Henkel, on the grounds that the bid was too low. Wella’s current market value nears $4 billion.