Homebuilder optimism is climbing as the spring selling season begins, according to the latest National Association of Home Builders index. The NAHB and Wells Fargo (WFC) survey builders to gauge perceptions of the new, single-family home market for the next six months. A score higher than 50 indicates more builders view the market as good than poor. The index stood at 16 for four months before inching up to 17 in March. NAHB Chairman Bob Nielsen said builders are "cautiously looking forward" to the upcoming spring home buying season, hoping an improving economy brings more buyers to the table. "However, the same factors that have been weighing down the market are still very much in play, particularly competition from short sales and foreclosures, consumers' inability to sell their existing home, appraisals that are coming in below construction cost due to the inappropriate use of distressed properties as comps, and restrictive lending conditions for both buyers and builders," Nielsen said. David Crowe, chief economist for the NAHB, said prevailing economic indicators point to "modest housing market gains later this year." Although some small homebuilders still aren't able to obtain credit for new construction. The NAHB said the index component that tracks current sales conditions remained flat with the prior month and the component that gauges traffic of prospective buyers also stayed flat, while sales expectations rose to 27, which is the highest level since May. Write to Jason Philyaw.