The Minimum Required Assets under the PMIERs are, in part, a function of the direct risk-in-force and the risk profile of the loans we insure, considering LTV ratio, credit score, vintage, Home Affordable Refinance Program ("HARP") status and delinquency status; and whether the loans were insured under lender-paid mortgage insurance policies or other policies that are not subject to automatic termination consistent with the Homeowners Protection Act requirements for borrower-paid mortgage insurance. Therefore, if our direct risk-in-force increases through increases in NIW, or if our mix of business changes to include loans with higher LTV ratios or lower FICO scores, for example, all other things equal, we will be required to hold more Available Assets in order to maintain GSE eligibility.
Depending on the actual life of a single premium policy and its premium rate relative to that of a monthly premium policy, a single premium policy may generate more or less premium than a monthly premium policy over its life. The percentage of our NIW from all single premium policies was 2.4% in 2024. Beginning in 2012, the annual percentage of our NIW from single premium policies has been as low as 2.4% in 2024 and as high as 20.4% in 2015.
As discussed in our risk factor titled "Reinsurance may be unavailable at current levels and prices, and/or the GSEs may reduce the amount of capital credit we receive for our reinsurance transactions," we have in place various QSR transactions. Although the transactions reduce our premiums, they have a lesser impact on our overall results, as losses ceded under the transactions reduce our losses incurred and the ceding commissions we receive reduce our underwriting expenses. The effect of the QSR transactions on the various components of pre-tax income will vary from period to period, depending on the level of ceded losses incurred. We also have in place various XOL reinsurance transactions under which we cede premiums. Under the XOL reinsurance transactions, for the respective reinsurance coverage periods, we retain the first layer of aggregate losses and the reinsurers provide second layer coverage up to the outstanding reinsurance coverage amount.
In addition to the effect of reinsurance on our premiums, if credit performance remains strong and loss ratios remain low, we expect a decline in our in force portfolio yield over time as competition in the industry results in lower premium rates. Refinance transactions on single premium policies benefit the yield due to the impact of accelerated earned premium from cancellation prior to their estimated life. Recent low levels of refinance transactions have reduced that benefit.
Our ability to rescind insurance coverage became more limited for new insurance written beginning in mid-2012, and it became further limited for new insurance written under our revised master policy that became effective March 1, 2020. These limitations may result in higher losses paid than would be the case under our previous master policies.
From time to time, in response to market conditions, we change the types of loans that we insure. We also may change our underwriting guidelines, including by agreeing with certain approval recommendations from a GSE automated underwriting system. We also make exceptions to our underwriting requirements on a loan-by-loan basis and for certain customer programs. Our underwriting requirements are available on our website at http://www.mgic.com/underwriting.
Even when home prices are stable or rising, mortgages with certain characteristics have higher probabilities of claims. As of December 31, 2024, mortgages with these characteristics in our primary risk in force included mortgages with LTV ratios greater than 95% (17%), mortgages with borrowers having FICO scores below 680 (6%), including those with borrowers having FICO scores of 620-679 (6%), mortgages with limited underwriting, including limited borrower documentation (1%), and mortgages with borrowers having DTI ratios greater than 45% (or where no ratio is available) (20%). Each attribute is determined at the time of loan origination. Loans with more than one of these attributes accounted for 5% of our primary risk in force as of December 31, 2024, and 5% and 4% of our primary risk in force as of December 31, 2023 and December 31, 2022, respectively. When home prices increase, interest rates increase and/or the percentage of our NIW from purchase transactions increases, our NIW on mortgages with higher LTV ratios and higher DTI ratios may increase. Our NIW on mortgages with LTV ratios greater than 95% was 14% in 2024 and 12% in 2023. Our NIW on mortgages with DTI ratios greater than 45% was 29% in 2024 and 26% in 2023. Our NIW on mortgages with borrowers having FICO scores less than 680 was 4.0% in 2024 and 4.2% in 2023.
From time to time, we change the processes we use to underwrite loans. For example: we rely on information provided to us by lenders that was obtained from certain of the GSEs' automated appraisal and income verification tools, which may produce results that differ from the results that would have been determined using different methods; we accept GSE appraisal waivers for certain loans; and we accept GSE appraisal flexibilities that allow property valuations in certain transactions to be based on appraisals that do not involve an onsite or interior inspection of the property. Our acceptance of automated GSE appraisal and income verification tools, GSE appraisal waivers and GSE appraisal flexibilities may affect our pricing and risk assessment. We also continue to further automate our underwriting processes and it is possible that our automated processes result in our insuring loans that we would have insured at a different premium rate or not otherwise have insured under our prior processes.
Approximately 71% of our NIW during 2024 and 2023 was originated under delegated underwriting programs pursuant to which the loan originators had authority on our behalf to underwrite the loans for our mortgage insurance. For loans originated through a delegated underwriting program, we depend on the originators' compliance with our guidelines and rely on the originators' representations that the loans being insured satisfy the underwriting guidelines, eligibility criteria and other requirements. While we have established systems and processes to monitor whether certain aspects of our underwriting guidelines were being followed by the originators, such systems may not ensure that the guidelines were being strictly followed at the time the loans were originated.
The widespread use of risk-based pricing systems by the private mortgage insurance industry (discussed in our risk factor titled "Competition or changes in our relationships with our customers could reduce our revenues, reduce our premium yields and / or increase our losses") makes it more difficult to compare our premium rates to those offered by our competitors. We may not be aware of industry rate changes until we observe that our mix of new insurance written has changed and our mix may fluctuate more as a result.
In March 2024, the National Association of Realtors ("NAR") reached a settlement agreement to resolve a series of lawsuits against it. As part of the settlement, NAR now prohibits the requirement that home sellers, through the seller's agent commission structure, offer to pay the real estate brokerage fees of homebuyers' real estate agents in order to list for-sale properties on NAR-affiliated Multiple Listing Services. If the expense of the buyer's agent commission is shifted to the buyer, it may negatively impact the ability of the buyer to secure financing.