Nissan officials are not expecting to reach a reborn alliance deal with Renault by the end of this year, as originally expected. The latest update comes from Reuters as several Nissan board members are expressing a more cautious approach to the talks. Renault, by contrast, would prefer to finalize the deal as soon as possible. What's holding it up?

Renault still wants Nissan to invest in its new electric vehicle unit that will be spun off as part of a major corporate-wide overhaul. In return, Nissan wants the French automaker to sell around 43% of the stake it currently holds in Nissan to place the two carmakers on a more even level.

Nissan only has a 15% stake in Renault. It's all about striking a balance, and Nissan believes it will never be in a better position to achieve its goals. But there are other unresolved issues.

Nissan officials are concerned, perhaps rightly so, about the transfer of intellectual property. Until that matter is resolved, no final deal can be signed. Nissan has invested heavily in electric vehicles, such as the new Ariya compact crossover. New governance rules also need to be established for the proposed revitalized alliance, another major concern for Nissan since the ousting of former alliance CEO Carlos Ghosn. Officials from both automakers declined to comment, and Japan's trade ministry is also urging Nissan to proceed carefully and slowly.

As for Renault, time is of the essence. Renault CEO Luca de Meo has proposed a turnaround plan to investors and they want to see it initiated as soon as possible. That plan involves bringing Nissan back into the fold.

But why is Nissan so concerned about its intellectual property with its own partner? Because Renault has separate but still unsigned deal with Chinese automaker Geely regarding its combustion engine business. Nissan, put simply, does not want the Chinese to steal its technology. Renault's future plans include separating into five businesses, increasing ties with Geely, and working with additional partners such as Airbus for batteries and Google on product design.