Fiat Chrysler May Have Taken Next Steps In Pursuing General Motors

may be prepping itself for a battle to fight back a forced tie-up with Big 3 peer

, according to sources cited

on Wednesday afternoon. Big banks like Goldman Sachs, Morgan Stanley and UBS have been tapped to advise GM, according to Reuters. As recently as June 9, The Wall Street Journal had reported Fiat Chrysler was

to take part in a potentially activist effort to push for a merger with GM. In late May, the New York Times suggested GM

from Fiat Chrysler earlier in 2015. According to Wednesday's Reuters report, "[GM CEO Mary] Barra's rejection has not stopped FCA boss Sergio Marchionne working on a merger plan, according to the sources. He is lobbying GM investors in an effort to drag the GM board to the negotiating table, they said... GM signed a letter of engagement with Goldman Sachs earlier this week seeking advice on FCA, one of the sources said." Shares of both GM and Fiat Chrysler were trading up in Thursday's post-market session. After GM closed up 0.5 percent at $35.80, the stock last traded at $35.98. Fiat Chrysler shares, meanwhile, were last indicated up nearly 3 percent to $15.60.