Protect your online virtual property, the highest potency item...

Can anyone tell me what does this mean?
''Protect your online virtual property, the highest potency item of its type in your inventory can not be vended''.

I get this message with some of my items. Does that mean that theses items are fake?

CPAdmin@
it means u cant get rid of the item unless
1. trade partners
2. market account
3. u gain a higher potency item

Do u think I'll be able to sell theses items with a market account?

what is the Market acc?

I think it means Merchant Account

Merchant account can sell anything, with only one condition
u cant sell cheaply
like a super item, u cant sell like $100, when u vend it, u need to put 2kk at least

which means, in order for u to trade items easily among accounts, constantly both accounts have like 10kk should be fine

Thx a lot for the tips.