You might think that landlords would welcome a tenant who offers to pay a year's rent in advance, but you would be wrong. Apparently, it simply looks suspicious.
"People who offer to pay all up front make landlords look for warning signs that prospective tenant is a money launderer, engaged in criminal enterprises, tax cheat, just out of rehab, a person with problems with prior landlords," explains a commenter in a StreetEasy.com discussion on the topic. Prepaid rent might also signal bad credit or unemployment. Moreover, it's not allowed in rent stabilized apartments and may be prohibited by a landlord's mortgage.
If you do find a landlord willing to take your money, you may be able to negotiate a discount.
"Expect them to select a very conservative discount rate (maybe 3%)," says one commenter. "I would also think that the likelihood of securing a higher discount rate would go up when dealing with a single-unit property owner (e.g. a condo) rather than a property management company. A single unit owner may benefit from the cash flow far more than a management company who 1) will see little to no benefit; and 2) may see the proposal as little more than an accounting burden."
Be aware, though, that paying up front may cost you leverage when it comes to resolving any problems that arise after you move in.
"The main disadvantage to the tenant is that if you have any problems with the landlord or with the apartment, you no longer have the one ace up your sleeve: ability to withhold rent."