Short answer. Article 2094 allows all movables within commerce to be pledged, provided they are susceptible of possession. That means personal property capable of being lawfully owned and transferred, and capable of actually being physically delivered or held, can serve as pledge collateral.
What the law says
All movables which are within commerce may be pledged, provided they are susceptible of possession.
Civil Code, Article 2094 — What May Be Pledged. Read the full provision →
Two conditions, both required
Article 2094 sets out two conditions a piece of property has to satisfy to be pledged: it must be a movable that is within commerce, and it must be susceptible of possession. Both conditions have to be met together. A movable that is within commerce but that cannot actually be possessed does not qualify under this article, and neither does something capable of possession that is not within commerce.
It has to be movable
The article confines pledge to movables — property that is not fixed to land or attached to real estate in a way that makes it immovable. This is what distinguishes a pledge from a mortgage in Philippine law: a pledge as described here is built around personal, movable property, not the land or fixtures that mortgage law instead deals with.
'Within commerce' excludes what cannot be privately dealt with
Being within commerce means the property is the kind of thing the law allows to be privately owned and transferred between persons — bought, sold, or otherwise dealt with. Property the law places outside ordinary private dealing does not meet this requirement, regardless of whether it happens to be a movable object in the physical sense. This is the same underlying idea used elsewhere in the code to mark the boundary of what a private person may own and freely transact over, and Article 2094 builds the pledge rule directly on top of it.
It also has to be capable of being possessed
Finally, the property has to be susceptible of possession — capable, that is, of actually being delivered into someone's physical control. This condition connects to how a pledge works in practice: since a pledge typically involves handing the thing pledged over to the pledgee, or otherwise placing it within their control, property that cannot be possessed in that way does not fit what Article 2094 contemplates as valid pledge collateral.
Reading the three requirements together
Article 2094 is best read as a short checklist rather than a single test: movable, within commerce, and susceptible of possession. Property that satisfies all three can be pledged under this article; property missing even one of them cannot, whatever else might make it valuable or important to the parties. Someone deciding what to offer, or accept, as pledge collateral is really asking whether the specific item in front of them clears all three of these requirements at once.