You are in luck. Beginning March 1, 2009, Fannie Mae will once again purchase loans from lenders for borrowers who have up to 10 financed properties.
Last June, Fannie Mae and Freddie Mac limited the total number of financed properties for loans delivered to Fannie or Freddie to just 4 per borrower, unless loan #5 was for a primary residence.
There are several minimum requirements, summarized below
Minimum middle credit score is 720.
30% down payment
6 months reserve requirements for ALL second home and investment financed properties, including the property you intend to purchase
No 30 day lates (or worse) on any mortgage in the past 12 months
No bankruptcy in the past 7 years
Reserve requirements means you must prove liquid reserves for mortgage principal, mortgage interest, property taxes, home owner's insurance, and association fees (if applicable). This is in addition to proving cash for down payment, closing costs, and any other reserves required by the lender. Reserves may be proven from cash savings, 401(k) plans (using 60% of vested balance), or from stock/investment portfolios.
Bear in mind that net rental income from your investment propreties will be a critical factor in determining your eligibility for a loan underwritten to Fannie Mae guidelines.
Only 75% of your net rental income may be used for qualifying purposes. Rental income must be supported by signed leases as well as proof of receipt of rent (such as bank statements showing deposits of rent).
Qualifying rental income will be determined from your net rental income from Schedule E of your tax return. Depreciation may be "added back" to your deductions for calculating taxable income from rent... but if Schedule E shows a profit on rent costs of less than 25% of your gross rents, you will need other sources of income to make up the difference for qualifying income.
Shopping around for lenders willing to underwirte loans under Fannie Mae's Lender Announcement 09-02 will be required. Many lenders will likely be unwilling to write the loan even if you meet all of Fannie's eligibility requirements. You will also likely be charged additional fees/higher interest rate for investment property loans beyond your first 4.
When calling prospective lenders, all that is needed is to ask if they will write loans under Fannie's Lender Announcement 09-02.
I also strongly advise you to see a full Pre-Approval (ie, submitting all of your documentation to an underwriter for a credit decision) prior to making an offer on a property to be sure the lender will approve the purchase.
Do not rely on "Pre-Qualifications" issued based on a review of your credit report and verbal informtion supplied by you. Loan originators have no authority to issue a credit decision... which is why "Pre-Qualfications" are educated guesses at best and utterly worthless at worst.
Here is the link to Fannie's Lender Announcement 09-02: