RTL, which earlier this year along with Five partner United Business Media held talks with Channel 4 about a possible merger, is asking the bank to consider all of its options, from increasing its stake to selling up if no options for expansion are seen.
Expansion or growth for RTL in the UK would call for Five to merge, but a merger with C4 is fraught with difficulty because of the station's state ownership.
The appointment of JP Morgan follows comments made in March when RTL Group chief executive Gerhard Zeiler said Five must find a partner within the next 18 months.
Another option could see it buy out the 35% stake held by Lord Hollick's UBM giving it full control of Five and more control over the station's future.
Lord Hollick has never said publicly that he wants to sell UBM's stake in Five but it is not a core asset to the firm's business, which is focused on research and business publishing.
Last year, RTL said that it would not sell its 65% stake in Five to Rupert Murdoch, although a tie-up with BSkyB could be another option.
Telewest is yet another avenue of opportunity. The cable firm owns Living TV, Bravo and Trouble through programming arm Flextech. In March, Five was reported to have held talks with US fund manager Bill Huff, who owns 20% of Telewest, about a possible collaboration between the two media companies.
Sources quoted by The Times said that JP Morgan has been hired "to assess all of Bertelsmann's strategic opportunities with Five".
If you have an opinion on this or any other issue raised on Brand Republic, join the debate in the .