中文摘要：

从企业商业关系网络视角，探讨客户关系对企业研发投资强度的影响。研究发现，客户集中度与企业研发投资强度呈现倒“U”型关系。进一步从企业的集团属性和地区金融发展水平研究发现，在非集团企业样本中，客户集中度与企业研发投资的倒“U”型关系依然存在，而在集团企业样本中，客户集中度与企业研发投资则显著负相关；同样地，在地区金融发展水平较高样本中，客户集中度与企业研发投资的倒“u”型关系依然存在，而在地区金融发展水平较低样本中，客户集中度与企业研发投资则显著负相关。研究表明企业的研发投资作为一种专用性资产投入，既具有在客户集中度方面的信号传递价值，还会在不同的融资约束情景下体现不同的投入强度，彰显其显著的环境调节功能，有助于企业多角度考量研发投资决策。

英文摘要：

From the perspective of enterprises＇ business relationship network, this paper discusses the influence of cus-tomer relationship on enterprises＇ R＆D investment intensity. The results show that the relationship between customer concen-tration and R＆D investment takes on an inverted-U shape. Further study of the effect of business group affiliation and local fi-nancial development on the relationship between customer concentration and R＆D investment finds that this inverted-U shapestill exists in non-group-affiliated firms, but the relationship between customer concentration and R＆D investment takes onnegative correlation in group-affiliated firms. Similarly, this inverted-U shape still exists in regions with a higher level of finan-cial development, but the relationship takes on negative correlation in regions with a lower level of financial development. Ourstudy also shows that as a kind of specific asset investment, enterprise＇s R＆D investment not only demonstrates its value of sig-nal transfer in terms of customer concentration, but also reflects different intensity in different financing constraints scenarios,highlighting its significant moderating effect. We hope these findings can help enterprises consider R＆D investment decisionsfrom multiple perspectives.