-емый

1. Formation
These participles are formed from the 3rd person plural ('они') form of imperfective transitive verbs by dropping the ending and adding a suffix:

• 1st Conjugation: Drop -ут/-ют and add -емый. For example, они читают → читаемый.
• 2nd Conjugation: Drop -ат/-ят and add -имый. For example, они любят → любимый (beloved/favorite).
• Mnemonic: The vowels in the participle suffixes (-ем- and -им-) perfectly match the vowels in the 1st person plural ('мы') verb endings (-ем and -им).
• Special Case (-авать, -знавать, -ставать): These verbs retain the -ва- suffix. For -ставать, this applies to transitive prefixed forms. For example, доставать (они достают) → доставаемый.
• Suffix -ом-: A small group of 1st conjugation verbs use -ом-, such as вести → ведомый. Note that искать forms the exceptional искомый from its infinitive stem (иск-) rather than its present tense stem (ищ-).
• Exception: The verb двигать (1st conjugation) forms two valid participles: the regular двигаемый (used for literal, physical movement) and the exceptional движимый (using the 2nd conjugation suffix, used metaphorically, e.g., движимый чувством — moved by a feeling, or in legal terms like движимое имущество — movable property).
• Stress: For 1st conjugation, stress usually matches the 'мы' form. However, the -ом- suffix is always stressed, and for verbs in -авать, the stress falls on -ва-. For 2nd conjugation, if the verb has fixed stress on the root (e.g., видеть → вижу), the participle is stressed on the root (видимый). If the verb has shifting stress or fixed end stress (e.g., любить → люблю; руководить → руковожу), the stress falls on the suffix -им- (любимый, руководимый).

2. Key Nuances

• Aspect Restriction: Perfective verbs cannot form present participles because they do not have a present tense.
• Transitivity and Reflexivity: While most are formed from verbs taking the accusative direct object, some verbs governing the instrumental case also form this participle (e.g., руководить → руководимый). Note that these participles cannot be formed from reflexive verbs (verbs ending in -ся).
• Lexical Gaps: Not all transitive verbs have this form. Many common verbs (e.g., писать, пить, ждать, брать, бить, шить, петь) lack a present passive participle. Use который or a present active participle with the reflexive suffix -ся (e.g., продающийся, моющийся) instead.
• Agent: To specify who performs the action, use the instrumental agent (e.g., изучаемый учёными — studied by scientists).
• Short Forms: Like adjectives, these participles have short forms (e.g., читаем, читаема, читаемо, читаемы) which are used as predicates in formal sentences.
• Punctuation: When a participial phrase comes after the noun it modifies, it must be set off by commas. If it comes before the noun, there is usually no comma.

3. Usage and Register
This form is highly formal, common in academic and legal contexts. In daily life, many have become standard adjectives, such as любимый (favorite) or необходимый (necessary).